Changelog

See the v4.0.0 release notes for an overview of what’s new in 4.0.0. Use lodash-migrate, lodash-codemods, & eslint-plugin-lodash to help migrate pre-4 lodash code to the latest release.

_v4.17.21

February 21, 2021 — Diff — Docs

• Prevent command injection through _.template's variable option
• Improve performance of toNumber, trim and trimEnd on large input strings

_v4.17.20

August 14, 2020 — Diff — Docs

• Fixed issue with dependencies mapping
• Ensured modularized files in the lodash package are up to date

_v4.17.19

July 8, 2020 — Diff — Docs

• Allowed _.sortedIndexBy methods to short-circuit for empty arrays
• Ensured _.orderBy accepts iteratee path arrays
• Ensured _.isEqual returns accurate results without depending on parameter order for circular references
• Sanitized sourceURL in _.template
• Fix prototype pollution bug in _.zipObjectDeep
• Note: releases of 4.17.16 to 4.17.18 of the lodash npm package were corrupted; please update to more recent versions

_v4.17.15

July 17, 2019 — Diff — Docs

• Removed unintentionally published project helper scripts

_v4.17.14

July 10, 2019 — Diff — Docs

• Reverted use of the "type" field in package.json of lodash-es

_v4.17.13

July 9, 2019 — Diff — Docs

• Fixed missing dependency of _createRound

_v4.17.12

July 9, 2019 — Diff — Docs

• Ensured _.ceil, _.floor, & _round handle Infinity consistently
• Ensured _.debounce clears old timers before starting new ones
• Ensured _.mergeWith always provides a stack to customizer
• Ensured additions to Object.prototype don’t break lodash initialization
• Ensured map and set clones contain custom properties of source values
• Fixed prototype pollution for _.defaultsDeep
• Fixed prototype pollution for _.template options

_v4.17.11

Sep. 12, 2018 — Diff — Docs

• Ensured _.merge handles function properties consistently regardless of number of sources
• Ensured Object.prototype is not augmented by _.merge
• Ensured placeholder properties are set on fp.convert() results
• Avoided ReDoS issue in _.words implementation

_v4.17.10

Apr. 24, 2018 — Diff — Docs

• Updated Lodash for better Node.js 10 support

_v4.17.5

Feb. 3, 2018 — Diff — Docs

• Ensured _.clone supports subclassed arrays
• Ensured _.cloneDeep works with cyclical maps & sets
• Ensured _.defaults avoids unnecessary source property access
• Ensured _.invert doesn’t error on inverted values without toString methods
• Ensured _.merge & _.mergeWith avoid augmenting __proto__ properties
• Ensured _.set supports paths with symbols
• Ensured _.words detects ordinals in compound words
• Ensured fp.update works with paths that refer to functions

_v4.17.4

Dec. 31, 2016 — Diff — Docs

• Ensured _.omit with deep paths doesn’t mutate object

_v4.17.3

Dec. 24, 2016 — Diff — Docs

• Added support for symbol properties to _.isEqual
• Ensured getSymbols helper only gets enumerable symbols
• Ensured _.startsWith avoids coercing position of undefined
• Flipped iteratee arguments for fp.reduceRight
• Removed the array length limit for lazy evaluation

_v4.17.2

Nov. 15, 2016 — Diff — Docs

• Ensured _.pick picks keys over paths
• Ensured _.spread doesn’t include arguments after those spread
• Fixed _.omit performance regression

_v4.17.1

Nov. 14, 2016 — Diff — Docs

• Ensured _.omit copies shallow path values by reference
• Ensured _.pick supports path arrays
• Ensured _.pickBy doesn’t treat keys with dots or brackets as deep paths

_v4.17.0

Nov. 13, 2016 — Diff — Docs

• Added deep path support to _.omit & _.pick
• Ensured fp.assignAllWith & fp.mergeAllWith accept more than two sources
• Made process.binding detection more cautious to avoid chatty debugging

_v4.16.6

Oct. 31, 2016 — Diff — Docs

• Ensured _.xor returns an empty array when comparing the same array

_v4.16.5

Oct. 30, 2016 — Diff — Docs

• Added support for ordinal numbers to _.words
• Ensured _.xor works with more than two arrays
• Ensuredfp.convert handles aliased & remapped methods
• Improved “fp” debugging
• Made “isType” methods resistant to toStringTag spoofing
• Made _.isEmpty exit early for nullish values
• Refined _.isError checks to avoid false positives for plain objects
• Simplified _.isElement

_v4.16.4

Oct. 6, 2016 — Diff — Docs

• Added support for buffers to _.transform
• Added support for typed arrays to _.isEmpty
• Ensured _.toString works on an array of symbols
• Fixed _.merge regression with buffers
• Normalized buffers & typed arrays keys in “keys” methods
• Split _.isArguments out for older & newer environments

_v4.16.3

Oct. 3, 2016 — Diff — Docs

• Added a _.runInContext check in the “fp” browser build
• Ensured _.defaultsDeep & _.merge consistently assign undefined values
• Fixed _.isFunction detection of Proxy in Safari 10
• Made _.isEqual treat buffers differently than Uint8Array values
• Removed es-sham requirement for older browsers

_v4.16.2

Sept. 25, 2016 — Diff — Docs

• Fixed _.sampleSize performance regression
• Made “clone” methods use newer Buffer APIs when available

_v4.16.1

Sept. 20, 2016 — Diff — Docs

• Fixed backtick removal of _.escape & _.unescape
• Improved parse time by 2x in V8

_v4.16.0

Sept. 19, 2016 — Diff — Docs

• Added fp.rangeStep & fp.rangeStepRight
• Added a cache limit to internal _.memoize use
• Avoided V8 de-opts in _.isElement, _.isObject, & _.isObjectLike
• Dropped backtick encoding from _.escape & _.unescape
• Dropped testing in Node.js 0.10 & 0.12
• Ensured __proto__ is treated as a regular key in assignments
• Fixed _.bind & _.partial performance regression
• Optimized _.concat

_v4.15.0

Aug. 12, 2016 — Diff — Docs

• Added Latin Extended-A block support to _.deburr
• Reduced dependencies of _.isEmpty & _.toNumber

_v4.14.2

Aug. 8, 2016 — Diff — Docs

• Ensured methods work with mocked Date.now, clearTimeout, & setTimeout
• Ensured paths of “set” methods overwrite primitives
• Ensured fp.nthArg returns a curried function
• Reduced dependencies of _.initial, _.merge, & _.tail
• Removed old JIT & engine bug guards

_v4.14.1

July 29, 2016 — Diff — Docs

• Ensured paths with consecutive empty brackets or dots are parsed correctly
• Ensured _.random & “range” methods coerce arguments to finite numbers
• Fixed circular reference detection in _.cloneDeep
• Removed global prerequisite for exports detection

_v4.14.0

July 24, 2016 — Diff — Docs

• Added _.conformsTo & _.defaultTo
• Added more “fp” aliases
• Added “All” variants of fp/assign, fp/defaults,fp/merge, & fp/zip methods
• Ensured debounced cancel uses clearTimeout
• Ensured the alias _.first supports shortcut fusion
• Ensured _.assignWith respects customizer results of undefined
• Ensured _.divide & _.multiply return 1 when no arguments are specified
• Ensured _.isEqual has transitive equivalence for circular references
• Fixed argument order of fp/zipObjectDeep
• Simplified resolving the global object
• Stopped unconditional global exports in the browser
• Made per method packages zero-dependency modules
• Made wrapped function toString results more debuggable
• Made “flatten” methods honor Symbol.isConcatSpreadable
• Made _.isEqual treat invalid dates as equivalent
• Made LARGE_ARRAY_SIZE check in stackSet align with others
• Optimized adding values to stacks by not inspecting all key-value pairs
• Optimized “isType” methods to use faster Node.js C++ helpers when available
• Optimized _.endsWith, _.negate, & _.startsWith

_v4.13.1

May 23, 2016 — Diff — Docs

• Ensured _.find & _.findLast provide the correct key param when iterating objects

_v4.13.0

May 22, 2016 — Diff — Docs

• Added _.stubArray, _.stubFalse, _.stubObject, _.stubString, & _.stubTrue
• Added fromIndex param to _.find, _.findIndex, _.findLast, & _.findLastIndex
• Ensured empty brackets & dots in paths are treated as empty property names
• Ensured _.pullAll works with the same value for array & values
• Ensured _.round works with large precision values
• Ensured _.throttle works with a system time of 0
• Made _.isNative throw if core-js is detected
• Simplified UMD exports
• Added fp/findFrom, fp/findIndexFrom, fp/findLastFrom, fp/findLastIndexFrom, fp/indexOfFrom, & fp/lastIndexOfFrom
• Fixed argument order of fp/differenceBy, fp/differenceWith, fp/intersectionBy, fp/intersectionWith, fp/without, fp/unionBy, fp/unionWith, fp/xorBy, & fp/xorWith

_v4.12.0

May 8, 2016 — Diff — Docs

• Added _.toFinite
• Added iteratee arity hints to “forEach” methods
• Added support for maps & sets to _.toPairs & _.toPairsIn
• Ensured _.merge doesn’t skip trailing function sources
• Ensured fp/forEach, fp/forIn, & fp/forOwn cap their iteratee arguments
• Ensured fp/update does not convert end of path to an object
• Ensured matches methods match arrays with duplicate values
• Optimized “flatten” methods
• Simplified _.concat
• Updated cache implementations

_v4.11.2

Apr. 21, 2016 — Diff — Docs

• Ensured _.pullAt correctly sorts indexes greater than 9
• Ensured _.words doesn’t treat punctuation as words
• Ensured -0 works as path arguments
• Ensured set methods like _.uniq & _.xor convert -0 to 0

_v4.11.1

Apr. 14, 2016 — Diff — Docs

• Added fp/pluck as an alias of fp/map
• Ensured _.debounce defers invoking func when leading is false & wait is 0

_v4.11.0

Apr. 13, 2016 — Diff — Docs

• Added _.nth
• Added _.matchesProperty shorthand support to _.sortBy
• Added support for contractions to case methods & _.words
• Avoided unnecessary array cloning in createRecurryWrapper & mergeData
• Ensured fp/over doesn’t cap its iteratee arguments
• Made _.head avoid accessing array when its length is 0

_v4.10.0

Apr. 11, 2016 — Diff — Docs

• Added isIterateeCall check to _.split
• Added fp/paths & fp/props as aliases of fp/at
• Added fp/propEq as an alias of fp/matchesProperty
• Ensured _.debounce queues a trailing call for subsequent debounced calls after maxWait
• Ensured _.split handles a limit of 0 correctly in Node.js v0.10
• Optimized handling of emojis in string methods
• Removed fp/mapObj & fp/propOf aliases

_v4.9.0

Apr. 8, 2016 — Diff — Docs

• Added back _.matchesProperty shorthand support to “over” methods
• Ensured _.split works with emojis
• Fixed malformed fp/toString & fp/valueOf modules

_v4.8.2

Apr. 4, 2016 — Diff — Docs

• Reverted _.matchesProperty shorthand support for “over” methods

_v4.8.1

Apr. 4, 2016 — Diff — Docs

• Fixed typo in fp/_falseOptions

_v4.8.0

Apr. 4, 2016 — Diff — Docs

• Added fp/placeholder module & fp/__ alias
• Added convert to unconverted “fp” methods
• Added _.matchesProperty shorthand support to “over” methods
• Avoided errors in older Firefoxes when coercing Promise to a string
• Ensured _.has returns false for nested nullish object values
• Ensured _.has treats nested sparse arrays consistently
• Fixed argument order of fp/overArgs
• Made _.chunk, _.repeat, & _.sampleSize default n to 1 instead of 0
• Optimized _.matchesProperty shorthand

_v4.7.0

Mar. 31, 2016 — Diff — Docs

• Added _.divide, _.flatMapDeep, _.flatMapDepth, _.meanBy, & _.multiply
• Added fp/convert, fp/invokeArgs, fp/invokeArgsMap, fp/padChars, fp/padCharsEnd, fp/padCharsStart, fp/restFrom, & fp/spreadFrom
• Added _.entries as an alias of _.toPairs
• Added _.entriesIn as an alias of _.toPairsIn
• Added several “fp” aliases
• Added support for buffers to _.isEmpty
• Added support for maps & sets to _.isEmpty & _.size
• Added support for deep cloning data views, maps, & sets
• Added symbol support to _.omit, _.toNumber, & _.toPath
• Avoided a JIT bug in Safari 9 for baseIteratee
• Ensured array sequence methods don’t error for falsey values
• Ensured _.concat casts non-array array values to arrays
• Ensured _.has returns false for nested inherited properties
• Ensured _.isEqual compares promises by reference
• Ensured _.isPlainObject returns false for objects with a custom [[Prototype]]
• Ensured _.mergeWith sources are cloned when customizer returns undefined
• Ensured _.startCase only uppercases the first character of each word
• Ensured _.words detects words where an all caps word is next to a capitalized word
• Fixed argument order of fp/bind, fp/bindKey, & fp/isEqualWith
• Fixed aliases fp/all, fp/any, & fp/anyPass
• Made _.result resolve values of functions as it deep crawls over them
• Memoized stringToPath
• Optimized _.pad, _.padEnd, _.padStart, & _.toNumber
• Refactored _.debounce to simplify, reduce timers, & fix bugs

_v4.6.1

Mar. 1, 2016 — Diff — Docs

• Optimized baseClone to avoid cloning symbols for internal use

_v4.6.0

Feb. 29, 2016 — Diff — Docs

• Added _.pullAllWith, _.update, & _.updateWith
• Added core.min.js & lodash.min.js to the “fp” module ignored list
• Ensured _.defaultsDeep does not overwrite regexp values
• Ensured _.isEqual works with maps & sets with circular references
• Ensured “fp” uses lodash as the default placeholder
• Ensured stack is popped after a recursive merge so that it doesn’t affect sibling properties
• Fixed order of arguments in “fp” docs
• Optimized baseIsEqualDeep by removing a typed array check & unnecessary stack creation
• Optimized _.assign, _.assignIn, & _.intersection
• Optimized _.merge to avoid deep cloning sources if a customizer is provided
• Removed dead code from getNative
• Replaced Symbol checks with Symbol methods checks

_v4.5.1

Feb. 21, 2016 — Diff — Docs

• Added core.min.js & lodash.min.js to the npm package
• Ensured placeholders persist through more than one curried call
• Ensured assignValue assigns values if they aren’t the same own value
• Ensured “fp” methods avoid unnecessary cloning
• Ensured fp/omitBy & fp/pickBy provide value & key params to iteratees
• Fixed arity of fp/orderBy
• Used getPrototypeOf to set inheritance when constructor is a function

_v4.5.0

Feb. 17, 2016 — Diff — Docs

• Enabled support for cloning expando properties of boolean, number, & string objects
• Ensured fp/convert wrappers support iteratee shorthands

_v4.4.0

Feb. 15, 2016 — Diff — Docs

• Added _.castArray & _.flattenDepth
• Fixed argument order of fp/inRange & fp/zipWith
• Enabled fp/convert to auto wrap lodash in the browser
• Enabled fp/convert to work when given lodash with options
• Ensured fp/convert options works when applied individually
• Ensured fp/convert works with category modules
• Ensured _.isError works with subclassed values
• Ensured _.merge deep clones array, typed-array, & plain-object sources
• Ensured a debounced maxWait timeout isn’t processed on a leading call when leading is false & there isn’t a max delay queued

_v4.3.0

Feb. 7, 2016 — Diff — Docs

• Added _.isArrayBuffer, _.isBuffer, _.isMap, _.isSet, _.isWeakMap, & _.isWeakSet
• Added options param to fp/convert
• Ensured default placeholder values are set for relevant method modules
• Ensured _.add & _.subtract return 0 when no arguments are given
• Ensured fp/gt, fp/gte, fp/lt, & fp/lte don’t have rearg applied
• Improved accuracy of _.debounce & _.throttle

_v4.2.1

Feb. 3, 2016 — Diff — Docs

• Added remap of fp/trim as fp/trimChars for chars param support
• Ensured wrapped _.bind, _.curry, & _.partial support placeholders
• Ensured fp/_baseConvert uses _.spread for _.partial wrapper
• Ensured fp/add & fp/subtract don’t have rearg applied

_v4.2.0

Feb. 2, 2016 — Diff — Docs

• Added fp/assoc & fp/assocPath as aliases of fp/set
• Added fp/dissoc & fp/dissocPath as aliases of fp/unset
• Added start param to _.spread
• Ensured _.attempt preserves custom errors
• Ensured fp/partial & fp/partialRight accept an args param
• Ensured fp/unset is immutable
• Ensured _.iteratee clones sources for _.matchesProperty shorthand
• Made _.flatMap a “Collection” method
• Removed global references from the npm package

_v4.1.0

Jan. 29, 2016 — Diff — Docs

• Added _.invertBy & _.zipObjectDeep
• Added cherry pickable “fp” method modules to the npm package
• Ensured fp/convert works with aliases
• Ensured _.clone & _.cloneDeep work on prototype objects
• Ensured _.mergeWith overwrites primitives with source object clones
• Ensured _.sum & _.sumBy return 0 for empty arrays
• Optimized _.isEmpty for objects
• Fixed argument order of fp/assign, fp/defaults, & fp/merge

_v4.0.1

Jan. 25, 2016 — Diff — Docs

• Added _.matches to the core build
• Added placeholder support to “fp” methods
• Added support for keycap emojis
• Ensured _.concat returns an empty array for nullish values
• Ensured _.each & _.eachRight aliases have the correct chain behavior
• Ensured _.defaultsDeep doesn’t convert function properties to objects
• Ensured _.fromPairs can consume results of _.toPairs
• Ensured _.isEqual compares objects unordered
• Ensured _.noConflict restores _ only if lodash is the current value
• Ensured _.words captures all-caps words
• Ensured _.words treats all-lower & all-upper postfixes as separate words
• Fixed “fp” mapping of several methods
• Made _.omitBy & _.pickBy provide a key param to iteratees

_v4.0.0

Jan. 12, 2016 — Diff — Docs

Compatibility Warnings

• Removed Bower & Component package support in favor of npm

• Dropped IE 6-8 support

• Use es5-shim, & optionally es6-shim, to enable support

• Made _#times, _#forEach, _#forIn, _#forOwn, & their right-forms implicitly end chain sequences

var wrapped = _([1, 2, 3]);

// in 3.10.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

// in 4.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the array

• Removed category names from module paths

 // in 3.10.1
 var chunk = require('lodash/array/chunk');

 // in 4.0.0
 var chunk = require('lodash/chunk');

• Removed _.pluck in favor of _.map with iteratee shorthand

var objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.pluck(objects, 'a'); // ➜ [1, 2]
_.map(objects, 'a'); // ➜ [1, 2]

// in 4.0.0
_.map(objects, 'a'); // ➜ [1, 2]

• Removed thisArg params from most methods because they were largely unused, complicated implementations, & can be tackled with _.bind, Function#bind, or arrow functions

 var objects = [{ 'a': 1 }, { 'a': 2 }];
 var context = { 'b': 5 };

 function callback(item) {
   return item.a + this.b;
 }

 // in 3.10.1
 _.map(objects, callback, context);

 // in 4.0.0
 _.map(objects, _.bind(callback, context));

• Split _.max & _.min into _.maxBy & _.minBy

var array = [1, 2, 3],
    objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.max(array); // ➜ 3
_.max(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.min(objects, 'a'); // ➜ { 'a': 1 }

// in 4.0.0
_.max(array); // ➜ 3
_.maxBy(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.minBy(objects, 'a'); // ➜ { 'a': 1 }

• Method removals
  • Removed _.support
  • Removed _.findWhere in favor of _.find with iteratee shorthand
  • Removed _.where in favor of _.filter with iteratee shorthand
  • Removed _.pluck in favor of _.map with iteratee shorthand
• Method renames
  • Renamed _.first to _.head
  • Renamed _.indexBy to _.keyBy
  • Renamed _.invoke to _.invokeMap
  • Renamed _.modArgs to _.overArgs
  • Renamed _.padLeft & _.padRight to _.padStart & _.padEnd
  • Renamed _.pairs to _.toPairs
  • Renamed _.rest to _.tail
  • Renamed _.restParam to _.rest
  • Renamed _.sortByOrder to _.orderBy
  • Renamed _.trimLeft & _.trimRight to _.trimStart & _.trimEnd
  • Renamed _.trunc to _.truncate
• Split out methods
  • Split _.assign & _.assignIn into _.assignWith & _.assignInWith
  • Split _.clone & _.cloneDeep into _.cloneWith & _.cloneDeepWith
  • Split _.indexOf & _.lastIndexOf into _.sortedIndexOf & _.sortedLastIndexOf
  • Split _.invert into _.invertBy (see v4.1.0)
  • Split _.isEqual into _.isEqualWith
  • Split _.isMatch into _.isMatchWith
  • Split _.max & _.min into _.maxBy & _.minBy
  • Split _.merge into _.mergeWith
  • Split _.omit & _.pick into _.omitBy & _.pickBy
  • Split _.sample into _.sampleSize
  • Split _.sortedIndex into _.sortedIndexBy
  • Split _.sortedLastIndex into _.sortedLastIndexBy
  • Split _.sum into _.sumBy
  • Split _.uniq into _.sortedUniq, _.sortedUniqBy, & _.uniqBy
  • Split _.zipObject into _.fromPairs
• Absorbed _.sortByAll into _.sortBy
• Changed the category of _.at to “Object”
• Changed the category of _.bindAll to “Util”
• Changed _.matchesProperty shorthand to an array of [path, srcValue]
• Enabled _.merge to assign undefined if the destination property doesn’t exist
• Made “By” methods like _.groupBy & _.sortBy provide a single param to iteratees
• Made _.add, _.max, _.min, & _.sum no longer coerce values to numbers
• Made _.capitalize uppercase the first character & lowercase the rest (see _.upperFirst)
• Made _.eq its own method instead of an alias for _.isEqual
• Made _.functions return only own method names
• Made _.max & _.min return undefined when passed an empty array
• Made _.words chainable by default
• Moved ./lodash.js to ./dist/lodash.js in the master branch
• Moved ./index.js to ./lodash.js in the npm branch
• Removed isDeep params from _.clone & _.flatten
• Removed multiValue param from _.invert
• Removed support for binding all methods by default from _.bindAll
• Removed func-first param signature from _.before & _.after

Low Risk Compatibility Warnings

• Dropped boolean options param support in _.debounce, _.mixin, & _.throttle
• Dropped support for boolean orders param in _.orderBy
• Made _.escapeRegExp align to the defunct ES7 proposal
• Made _.max, _.min, & _.sum support arrays only
• Removed legacy options param signature from _.template

Notable Changes

• Core build

  • 4 kB (gzipped) core build (64 methods; Backbone ≥ v1.3.0 compatible)
    _.assignIn, _.before, _.bind, _.chain, _.clone, _.compact, _.concat, _.create, _.defaults, _.defer, _.delay, _.each, _.escape, _.every, _.filter, _.find, _.first, _.flatten, _.flattenDeep, _.forEach, _.has, _.head, _.identity, _.indexOf, _.isArguments, _.isArray, _.isBoolean, _.isDate, _.isEmpty, _.isEqual, _.isFinite, _.isFunction, _.isNaN, _.isNull, _.isNumber, _.isObject, _.isRegExp, _.isString, _.isUndefined, _.iteratee, _.keys, _.last, _.map, _.matches, _max, _.min, _.mixin, _.negate, _.noConflict, _.noop, _.once, _.pick, _.reduce, _.result, _.size, _.slice, _.some, _.sortBy, _.tap, _.thru, _.toArray, _.uniqueId, _#value, & _.values
  • Reduced functionality:
    • Cloning only supports arrays & Object objects
    • Iteratee shorthand for _.matchesProperty is removed
    • Lazy evaluation is removed
    • Placeholder support is removed
    • Support for deep property paths is removed
    • Support for maps, sets, & typed arrays is removed

• Added 80 methods

  • 22 array methods:
    _.concat, _.differenceBy, _.differenceWith, _.fromPairs, _.intersectionBy, _.intersectionWith, _.join, _.pullAll, _.pullAllBy, _.reverse, _.sortedIndexBy, _.sortedIndexOf, _.sortedLastIndexBy, _.sortedLastIndexOf, _.sortedUniq, _.sortedUniqBy, _.unionBy, _.unionWith, _.uniqBy, _.uniqWith, _.xorBy, & _.xorWith

  • 18 lang methods:
    _.cloneDeepWith, _.cloneWith, _.eq, _.isArrayLike, _.isArrayLikeObject, _.isEqualWith, _.isInteger, _.isLength, _.isMatchWith, _.isNil, _.isObjectLike, _.isSafeInteger, _.isSymbol, _.toInteger, _.toLength, _.toNumber, _.toSafeInteger, & _.toString

  • 13 object methods:
    _.assignIn, _.assignInWith, _.assignWith, _.functionsIn, _.hasIn, _.invoke, _.mergeWith, _.omitBy, _.pickBy, _.setWith, _.toPairs, _.toPairsIn, & _.unset

  • 8 string methods:
    _.lowerCase, _.lowerFirst, _.replace, _.split, _.upperCase, _.upperFirst, _.toLower, & _.toUpper

  • 8 utility methods:
    _.cond, _.conforms, _.nthArg, _.over, _.overEvery, _.overSome, _.rangeRight, & _.toPath

  • 4 math methods:
    _.maxBy, _.mean, _.minBy, & _.sumBy

  • 2 collection methods:
    _.flatMap (see v4.2.0) & _.sampleSize

  • 2 function methods:
    _.flip & _.unary

  • 2 number methods:
    _.clamp & _.subtract

  • 1 chain method:
    _#next

• Added 3 aliases

  • Added _.extend as an alias of _.assignIn
  • Added _.extendWith as an alias of _.assignInWith
  • Added _.first as an alias of _.head

• Removed 17 aliases

  • Removed _.all in favor of _.every
  • Removed _.any in favor of _.some
  • Removed _.backflow in favor of _.flowRight
  • Removed _.callback in favor of _.iteratee
  • Removed _.collect in favor of _.map
  • Removed _.compose in favor of _.flowRight
  • Removed _.contains in favor of _.includes
  • Removed _.detect in favor of _.find
  • Removed _.foldl in favor of _.reduce
  • Removed _.foldr in favor of _.reduceRight
  • Removed _.include in favor of _.includes
  • Removed _.inject in favor of _.reduce
  • Removed _.methods in favor of _.functions
  • Removed _.object in favor of _.fromPairs or _.zipObject
  • Removed _#run in favor of _#value
  • Removed _.select in favor of _.filter
  • Removed _.unique in favor of _.uniq instead

• Performance improvements

  • Enabled shortcut fusion for _.at, _.find & _.findLast
  • Optimized match methods to avoid deep crawling if object & source identical
  • Optimized circular reference searches
  • Optimized _.isEqual to avoid stack crawls when arrays or objects are different sizes

• Emoji support

  • Added support for astral symbols, combining diacritical marks, dingbats, regional indicator symbols, unicode modifiers, variation selectors, & zero-width-joiners to string methods

• Functional goodies

  • Added _.cond, _.conforms, _.flip, _.nthArg, _.over, _.overEvery, _.overSome, & _.unary
  • Moved lodash-fp into lodash as require('lodash/fp') for immutable auto-curried iteratee-first data-last methods

Other Changes

• Added clear method to _.memoize.Cache
• Added flush method to debounced & throttled functions
• Added support for maps, sets, & symbols to _.clone, _.isEqual, & _.toArray
• Added support for array buffers to _.isEqual
• Added support for converting iterators to _.toArray
• Added support for deep paths to _.zipObject
• Changed UMD to export to window or self when available regardless of other exports
• Enabled _.flow & _.flowRight to accept an array of functions
• Ensured “Collection” methods treat functions as objects
• Ensured debounce cancel clears args & thisArg references
• Ensured _.add & _.sum don’t skip NaN values
• Ensured _.assign, _.defaults, & _.merge coerce object values to objects
• Ensured _.bindKey bound functions call object[key] when called with the new operator
• Ensured _.clone treats generators like functions
• Ensured _.clone produces clones with the source’s [[Prototype]]
• Ensured _.defaults assigns properties that shadow Object.prototype
• Ensured _.defaultsDeep doesn’t merge a string into an array
• Ensured _.defaultsDeep & _.merge don’t modify sources
• Ensured _.defaultsDeep works with circular references
• Ensured _.isFunction returns true for generator functions
• Ensured _.keys skips “length” on strict mode arguments objects in Safari 9
• Ensured _.merge assigns typed arrays directly
• Ensured _.merge doesn’t convert strings to arrays
• Ensured _.merge merges plain-objects onto non plain-objects
• Ensured _#plant resets iterator data of cloned sequences
• Ensured _.random swaps min & max if min is greater than max
• Ensured _.range preserves the sign of start of -0
• Ensured _.reduce & _.reduceRight use getIteratee in their array branch
• Fixed rounding issue with the precision param of _.floor
• Made _(...) an iterator & iterable
• Made _.drop, _.take, & right forms coerce n of undefined to 0

_v3.10.1

Aug. 4, 2015 — Diff — Docs

• Ensured func is a function before calling getData
• Ensured _.clone provides the correct number of arguments to customizer
• Ensured _#reverse doesn’t modify the original array when called after _#slice

_v3.10.0

June 30, 2015 — Diff — Docs

• Added _.ceil, _.defaultsDeep, _.floor, _.modArgs, & _.round
• Ensured _.bind works with all built-in constructors
• Ensured _#concat treats sparse arrays as dense
• Ensured _.chunk floors size values
• Ensured _.debounce & _.throttle reset lastCall after cancelling
• Ensure _.flow & _.flowRight work with functions combined with _.first
• Ensured _.indexOf returns -1 for unmatched binary searches
• Ensured _.noConflict operates on root & not context
• Made _.escapeRegExp more robust
• Made _.sortByOrder support orders of “asc” & “desc”
• Optimized _.flatten, _.max, & _.min
• Removed fallbacks for _.isArguments, _.isFunction, & _.isPlainObject
• Simplified lazy evaluation support
• Simplified _.isElement, _.isFinite, _.isNative, _.now, _.parseInt, & _.sum

_v3.9.3

May 26, 2015 — Diff — Docs

• Made parseFloat assigned from the context param of _.runInContext
• Ensured _.set handles non-index property names that start with numbers correctly

_v3.9.2

May 24, 2015 — Diff — Docs

• Made isLaziable work with wrapped lodash methods
• Optimized an early exit case in _.isEqual
• Optimized _.sample

_v3.9.0

May 19, 2015 — Diff — Docs

• Added _.gt, _.gte, _.lt, & _.lte
• Added support for an ImmutableMap to _.memoize.Cache
• Avoided using require in source comments to improve browserify build times
• Ensured baseCreate works in ExtendScript
• Ensured customizer results are respected by _.isEqual
• Ensured LodashWrapper.prototype.thru exists before creating a wrapper in flow
• Ensured _.bind works with ES2015 class constructors
• Ensured _.get can return null values
• Ensured _.intersection works with a single array
• Ensured _.has treats sparse arrays as dense
• Ensured _.merge skips undefined array values if a destination value exists
• Made null sort behind undefined & NaN
• Made _.eq an alias of _.isEqual
• Optimized object comparisons in _.isEqual
• Optimized _.max & _.min when invoked with iteratees
• Optimized _.pullAt & _.remove
• Used hasOwnProperty for the creation of reIsNative to avoid issues with core-js

_v3.8.0

May 1, 2015 — Diff — Docs

• Added _.mapKeys, _.unzipWith, & _.zipWith
• Made _.difference, _.intersection, _.uniq, & _.xor accept array-like values
• Ensured empty brackets are ignored by _.get & _.set
• Ensured baseAt, basePullAt, & pullAt handle nullish values
• Ensured baseGet only returns undefined for incomplete paths
• Ensured _.padLeft & _.padRight handle empty strings correctly
• Made _.isEqual treat -0 & 0 as equivalent
• Narrowed bitmask checks in _.flow & _.flowRight
• Optimized lazy slice for start of 0
• Optimized “flatten” methods
• Restricted Object.assign use to strict mode only

_v3.7.0

Apr. 15, 2015 — Diff — Docs

• Added _.get, _.method, _.methodOf, & _.set
• Avoided a JIT bug in Safari on at least iOS 8.1-8.3 ARM64
• Ensured _.intersection of a single array returns an empty array
• Ensured _.remove mutates array after the predicate pass
• Ensured methods like _.has & _.get can access index values of strings
• Made createAssigner & _.sortByAll use _.restParam
• Made _.add coerce augend & addend params to numbers
• Made _.assign use built-in Object.assign when available
• Made _.inRange swap start & end params when start is greater than end
• Added deep path support to methods like _.has, _.get, _.callback, _.invoke, _.matchesProperty, _.method, _.methodOf, _.property, _.propertyOf, _.result, & _.set

_v3.6.0

Mar. 25, 2015 — Diff — Docs

• Added _.restParam
• Added isIterateeCall guards to _.every, _.includes, & _.some
• Added support for iteratee & thisArg params to _.sum
• Added support for shortcut fusion optimizations to _.flow & _.flowRight
• Ensured lodash bundled by r.js runs in a web worker
• Ensured _.deburr removes combining diacritical marks
• Ensured _.difference is based on the values of the first param only
• Expanded metadata optimizations to more combinations of curried functions
• Made _.matches work with non-plain objects & match inherited properties
• Optimized _.findLast, _.reduce, & _.reduceRight
• Reduced code duplication with internal method creator functions

_v3.5.0

Mar. 8, 2015 — Diff — Docs

• Added string replace & split chaining methods
• Ensured lazy drop works when applied after filter
• Optimized curried method performance

_v3.4.0

Mar. 6, 2015 — Diff — Docs

• Added _.add, _.sortByOrder, & _.sum
• Adjusted root to work when bundled by webpack & running in a web worker
• Ensured lazy chaining works with combinations of drop & dropWhile
• Ensured _.defaults works as an iteratee for _.reduce
• Reduced side effects of shortcut fusion
• Optimized baseFlatten, baseIndexOf, indexOfNaN, _.flow, & _.flowRight
• Optimized lazy evaluation for iteratees with one param

_v3.3.1

Feb. 24, 2015 — Diff — Docs

• Ensured lazy takeWhile works with lazy reverse & last
• Ensured wait defaults to 0 for _.debounce & _.throttle
• Ensured isIterateeCall doesn’t error if index is missing a toString method
• Optimized _.difference, _.intersection, & _.uniq in Firefox

_v3.3.0

Feb. 20, 2015 — Diff — Docs

• Added _.inRange
• Added links to each method’s npm package to the documentation
• Enabled _.clone to work with more truthy isDeep values
• Ensured each lodash wrapper module sets up their inheritance
• Ensured isIterateeCall works with NaN values
• Ensured _.merge avoids iterating string object or source params
• Optimized _.attempt
• Reduced nested dependencies of _.template

_v3.2.0

Feb. 12, 2015 — Diff — Docs

• Added _.fill, _.matchesProperty, & _.spread
• Added _#commit & _#plant
• Added support for lazy _.compact & _.toArray
• Enabled _.attempt to provide additional arguments to func
• Ensured _.flow returns an identity function when called without arguments
• Ensured _#reverse tracks __chain__ values
• Ensured lazy _.slice handles floating-point start & end params
• Fixed lazy _.slice when used after _.filter
• Made _#run an alias of _#value

_v3.1.0

Feb. 3, 2015 — Diff — Docs

• Added _.startCase
• Ensured isIterateeCall works correctly with objects

_v3.0.1

Jan. 30, 2015 — Diff — Docs

• Ensured _.slice coerces floating-point start & end params to integers
• Fixed lazy initial, rest, & reverse
• Fixed _.merge regression with DOM elements

_v3.0.0

Jan. 26, 2015 — Diff — Docs

Compatibility Warnings

• Made chaining lazy, that is, execution is deferred until _#value is implicitly or explicitly called

var wrapped = _([1, 2, 3]);

// in 2.4.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the lodash wrapper

// in 3.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

• Ensured each segment of a chain sequence may be repeatly applied

var array = [1],
    wrapped = _(array);

// in 2.4.1
var a = wrapped.push(2), // pushes `2` to `array`
    b = wrapped.push(3); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

// in 3.0.0
var a = wrapped.push(2), // creates a lazy sequence to push `2` to `array`
    b = wrapped.push(3); // creates a lazy sequence to push `3` to `array`

a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3]
a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2, 3, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3, 2, 3]

// use `_#commit` to commit a sequence and continue chaining
var a = wrapped.push(2).commit(), // pushes `2` to `array`
    b = wrapped.push(3).commit(); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

• Made _.flatten shallow by default & remove callback support

var array = [1, [[2], 3]],
    objects = [{ 'a': [1] }, { 'a': [2, 3] }];

// in 2.4.1
_.flatten(array); // ➜ [1, 2, 3]
_.flatten(objects, 'a'); // [1, 2, 3]

// in 3.0.0
_.flatten(array); // ➜ [1, [2], 3]
_.flattenDeep(array); // ➜ [1, 2, 3]
_(objects).pluck('a').flatten().value(); // [1, 2, 3]

• Removed the data parameter from _.template

var string = '<%= o.a %>',
    options = { 'variable': 'o' },
    data = { 'a': 'b' };

// in 2.4.1
_.template(string, data, options); // ➜ 'b'

// in 3.0.0
_.template(string, options)(data); // ➜ 'b'

• Split _.first & _.last into _.take, _.takeWhile, _.takeRight, & _.takeRightWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.first(array); // ➜ 1
_.first(array, 2); // ➜ [1, 2]
_.first(array, lessThanTwo);   // ➜ [1]

_.last(array); // ➜ 3
_.last(array, 2); // ➜ [2, 3]
_.last(array, greaterThanTwo); // ➜ [3]

// in 3.0.0
_.first(array); // ➜ 1
_.take(array, 2); // ➜ [1, 2]
_.takeWhile(array, lessThanTwo); // ➜ [1]

_.last(array); // ➜ 3
_.takeRight(array, 2); // ➜ [2, 3]
_.takeRightWhile(array, greaterThanTwo); // ➜ [3]

• Split _.initial & _.rest into _.dropRight, _.dropRightWhile, _.drop, & _.dropWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.initial(array); // ➜ [1, 2]
_.initial(array, 2); // ➜ [1]
_.initial(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.rest(array, 2); // ➜ [3]
_.rest(array, lessThanTwo); // ➜ [2, 3]

// in 3.0.0
_.initial(array); // ➜ [1, 2]
_.dropRight(array, 2); // ➜ [1]
_.dropRightWhile(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.drop(array, 2); // ➜ [3]
_.dropWhile(array, lessThanTwo); // ➜ [2, 3]

• Aligned _.isFinite & _.keys with ES2015
• Changed the category of _.clone & _.cloneDeep, & “isType” methods from “Object” to “Lang”
• Changed the category of _.escape, _.template, & _.unescape from “Util” to “String”
• Changed the category of _.range from “Array” to “Util”
• Changed the category of _.toArray from “Collection” to “Lang”
• Made method categories singular
• Made “Object” methods coerce primitives to objects
• Made _.clone & _.cloneDeep return a new object for unsupported types
• Made _.findWhere its own method instead of an alias for _.find
• Made _.max & _.min non-chainable by default
• Made _.memoize caches have the Map interface of delete, get, has, & set
• Made _.unzip its own method instead of an alias for _.zip
• Moved ./dist/lodash.js to ./lodash.js in the master branch
• Moved ./dist/lodash.js to ./lodash.js in the npm branch
• Moved ./dist/lodash.compat.js to the lodash/lodash-compat repository
• Moved support for sorting by multiple properties from _.sortBy to _.sortByAll
• Removed result sorting from _.functions
• Removed the underscore build
• Renamed _.createCallback to _.callback
• Renamed _.support.argsClass to _.support.argsTag
• Renamed _.support.nodeClass to _.support.nodeTag
• Restricted _.mixin to iterating only own properties of source objects
• Expanded the number of arguments provided to customizer callbacks of _.assign,
  _.clone, _.cloneDeep, _.isEqual, & _.merge

Low Risk Compatibility Warnings

• Added customizable argument placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
• Added support for matching NaN to _.difference, _.includes, _.indexOf, _.intersection, _.lastIndexOf, _.union, _.uniq, & _.xor
• Ensured _.assign & _.merge don’t assign customizer results if it’s unchanged
• Ensured _.mixin doesn’t extend lodash when given an empty options object
• Ensured _.sortedIndex returns values that align with the sort order of _.sortBy
• Ensured functions of _.matches return true when comparing empty sources
• Ensured functions of _.matches perform own property checks on objects
• Made _.chain use an existing wrapper if available instead of creating a new wrapper
• Removed the argCount parameter from _.callback

Notable Changes

• Added 47 methods

• 17 string methods:
  _.camelCase, _.capitalize, _.deburr, _.endsWith, _.escapeRegExp, _.kebabCase, _.pad, _.padLeft, _.padRight, _.repeat, _.snakeCase, _.startsWith, _.trim, _.trimLeft, _.trimRight, _.trunc, & _.words

• 11 array methods:
  _.chunk, _.dropRight, _.dropRightWhile, _.dropWhile, _.flattenDeep, _.pullAt, _.slice, _.sortedLastIndex, _.takeRight, _.takeRightWhile, & _.takeWhile

• 6 function methods:
  _.ary, _.before, _.curryRight, _.flow, _.negate, & _.rearg

• 5 lang methods:
  _.isError, _.isMatch, _.isNative, _.isTypedArray, & _.toPlainObject

• 3 utility methods:
  _.attempt, _.matches, & _.propertyOf

• 2 collection methods:
  _.partition & _.sortByAll

• 2 object methods:
  _.keysIn & _.valuesIn

• 1 chain method:
  _.thru

• Added 5 aliases

• Added _.backflow & _.compose as aliases of _.flowRight
• Added _.contains as an alias of _.includes
• Added _.iteratee as an alias of _.callback
• Added _#toJSON as an alias of _#valueOf

• Performance improvements

• Improved overall performance 20-40%
• Method chaining supports lazy evaluation
• Methods with support for shortcut fusion:
  _.drop, _.dropRight, _.dropRightWhile, _.dropWhile, _.filter, _.first, _.initial, _.last, _.map, _.pluck, _.reject, _.rest, _.reverse, _.slice, _.take, _.takeRight, _.takeRightWhile, _.takeWhile, & _.where
• Other optimized methods:
  _.bind, _.clone, _.cloneDeep, _.compact, _.compose, _.contains, _.difference, _.escape, _.flatten, _.invoke, _.isEqual, _.isObject, _.matches, _.max, _.min, _.partial, _.shuffle, _.unescape, _.uniq, _.without, & _.zip

• Functional goodies

• Added _.ary, _.curryRight, _.flow, & _.rearg
• Added placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
• Methods that work as an iteratee for _.map, & the like, out of the box:
  _.ary, _.callback, _.chunk, _.clone, _.create, _.curry, _.curryRight, _.drop, _.dropRight, _.flatten, _.invert, _.max, _.min, _.parseInt, _.slice, _.sortBy, _.take, _.takeRight, _.template, _.trim, _.trimLeft, _.trimRight, _.trunc, _.random, _.range, _.sample, _.uniq, & _.words
• Methods that work as an iteratee for _.reduce, & the like, out of the box:
  _.assign, _.defaults, _.merge, & _.sortAllBy

Other Changes

• Added cherry pickable method modules to the npm package
• Added cancel method to debounced & throttled functions
• Added defaultValue param to _.result
• Added multiValue param to _.invert
• Added thisArg param to _.tap
• Added _.memoize.Cache to enable Map/WeakMap to be used
• Added support for cloning array buffers & typed arrays to _.clone & _.cloneDeep
• Added support for comparing error objects & typed arrays to _.isEqual
• Enabled the sourceURL option of _.template to work in production builds
• Ensured _.at, _.matches, & _.pullAt work with falsey values when keys are given
• Ensured _.callback doesn’t error when func is nullish & thisArg is given
• Ensured _.callback supports binding built-in methods
• Ensured _.debounce & _.throttle work if the system time is set backwards
• Ensured _.difference works with arrays regardless of argument position
• Ensured _.findWhere & _.where always use _.matches
• Ensured _.includes supports fromIndex when iterating objects
• Ensured _.indexOf([], undefined, true) returns -1 instead of 0
• Ensured _.intersection ignores non-array secondary values
• Ensured _.isEqual works with wrapped objects containing constructor properties
• Ensured _.keys treats sparse arrays as dense
• Ensured _.keys works with string objects in IE < 9
• Ensured _.matches comparison isn’t affected by changes to source objects
• Ensured _.max & _.min return the correct value when callback computes ±Infinity
• Ensured _.merge ignores undefined values of source object properties
• Ensured _.partial & _.partialRight work with curried functions
• Ensured _.pluck always uses _.property
• Ensured _.random returns 1 or 0 when called with no arguments
• Ensured _.range, _.slice, & other methods handle NaN arguments
• Ensured _.runInContext uses a zeroed _.uniqueId counter
• Ensured _.transform checks that object is an object before using its [[Prototype]]
• Ensured _.where handles source objects with undefined property values
• Ensured _.where only returns elements that contain all source array/object values
• Ensured browserified lodash works in web workers
• Ensured customizing _.indexOf affects _.includes when iterating objects
• Ensured lodash works in NW.js
• Ensured lodash doesn’t add Function.prototype extensions to its prototype
• Fixed _.isFunction for typed array constructors in Safari 8
• Made _.escape & _.unescape handle backticks
• Made _.isElement more robust
• Made _.parseInt more closely follow spec
• Made _.wrap use _.identity when wrapper is nullish
• Made templates avoid referencing _.escape if “escape” delimiters are not used
• Made array-like object checks follow ES2015 ToLength
• Made use of Set in _.difference, _.intersection, & _.uniq
• Removed array & object pools
• Removed all method compilation from the compat build
• Updated the sourceURL syntax used by _.template

_v2.4.2

Apr. 26, 2015 — Diff — Docs

• Avoided memory leaks in _.bind, _.bindKey, _.curry, _.partial, & _.partialRight

_v2.4.1

Dec. 2, 2013 — Diff — Docs

• Ensured __bindData__ is properly cloned
• Ensured _.isEqual can compare cyclical objects with shared property values
• Optimized _.partial & _.partialRight
• Reached ~100% code coverage

_v2.4.0

Nov. 25, 2013 — Diff — Docs

• Added _.constant, _.mapValues, _.now, _.property, & _.xor
• Added an options param to _.mixin to specify whether functions added are chainable
• Added support for _.sortBy to accept an array of property names to sort by
• Enabled _.zipObject to accept an array of keys with no values param
• Removed conditional setImmediate use from _.defer

_v2.3.0

Nov. 10, 2013 — Diff — Docs

• Added _.create & _.noop
• Avoided memory leaks in _.debounce & _.throttle
• Enhanced _.createCallback to avoid binding functions bound by Function#bind
• Ensured rebound functions correctly partially apply arguments
• Ensured _.isEqual works with values from Object.create(null) & _(false)
• Ensured _.min & _.max work as callbacks for _.map
• Ensured _.template coerces the text param to a string
• Optimized _.difference, _.omit, & _.without by way of baseDifference
• Optimized _.isBoolean, _.isNumber, & _.isString for the false case
• Optimized _.sample & _.shuffle by way of baseRandom
• Reduced _.wrap by way of createBound
• Removed native Function#bind use for better cross-environment consistency

_v2.2.1

Oct. 3, 2013 — Diff — Docs

• Ensured _.mixin creates functions that work with _.chain
• Ensured the the createObject fallback is included in the modern build

_v2.2.0

Sept. 28, 2013 — Diff — Docs

• Added _.clone support for date, regexp, & other built-in objects
• Ensured _.random avoids excessive results of 0 for floating-point numbers
• Made compat & underscore builds use Date.now when available
• Reduced dependencies on getObject & releaseObject

_v2.1.0

Sept. 22, 2013 — Diff — Docs

• Added Object.defineProperty fallback for the modern build
• Added support to _.random to explicitly specify floating point numbers
• Enabled _.compose to be invoked without arguments
• Ensured _.flatten works with extremely large arrays
• Ensured _.support properties aren’t minified
• Ensured reThis isn’t used in Windows 8 applications
• Made UMD more resistant to false positives
• Optimized _.isArguments & _.isArray fallbacks

_v2.0.0

Sept. 13, 2013 — Diff — Docs

Compatibility Warnings

• Aligned _.after with Underscore 1.5.0, making it always return a function
• Made _.unzip an alias of _.zip

Notable Changes

• Created lodash methods as npm packages & AMD/Node.js modules
• Made _.chain force chaining for all methods
• Moved the build utility to lodash-cli
• Optimized _.contains, _.debounce, _.isArguments, _.throttle, & _.where
• Optimized functions of _.bind, _.bindKey, _.curry, _.partial, & _.partialRight
• Added _.curry, _.forEachRight, _.indexBy, _.findLast, _.findLastIndex, _.findLastKey, _.forInRight, _.forOwnRight, _.pull, _.remove, & _.sample

Other Changes

• Added Curl & Dojo module loaders to the unit tests
• Added the modularize build option
• Added support for the iife command to be used without an %output% token
• Added support for _.mixin to accept a destination object
• Added support for _.range to accept a step of 0
• Ensured “Array” methods support arguments objects
• Ensured “Function” methods throw on non-functions
• Ensured _.at works as a callback for _.map
• Ensured _.createCallback works when no argCount is specified
• Ensured _.first & _.last return arrays when given an n with a falsey array
• Ensured _.flatten works with arguments objects
• Ensured minified files work with Dojo’s builder
• Ensured _.zipObject skips falsey elements
• Improved dead code removal from builds
• Improved JSDoc syntax
• Made _.eachRight an alias of _.forEachRight
• Made _.memoize avoid prefixing cache keys when using a resolver function
• Removed local clearTimeout & setTimeout variables from the underscore build
• Reduced the size of the repo & npm package
• Simplified the bailout in createCache
• Updated sourceURL & sourceMappingURL syntax
• Updated underscore build compatibility to v1.5.2

_v1.3.1

June 12, 2013 — Diff — Docs

• Added missing cache property to the objects returned by getObject
• Ensured maxWait unit tests pass in Ringo
• Increased the maxPoolSize value
• Optimized releaseArray & releaseObject

_v1.3.0

June 11, 2013 — Diff — Docs

• Added _.transform
• Added _.chain & _.findWhere aliases
• Added internal array & object pooling
• Added Istanbul test coverage reports to Travis CI
• Added maxWait option to _.debounce
• Added support for floating point numbers to _.random
• Added Volo configuration to package.json
• Adjusted UMD for component build
• Enabled more stable mixing of lodash & underscore build methods
• Ensured debounced function with leading & trailing options works as expected
• Ensured minified builds work with the Dojo builder
• Ensured minification avoids deoptimizing expressions containing boolean values
• Ensured support for --output paths containing build command keywords
• Ensured unknown types return false in _.isObject & _.isRegExp
• Ensured _.clone, _.flatten, & _.uniq can be used as callback for _.map
• Ensured _.forIn works on objects with longer inheritance chains in IE < 9
• Ensured _.isPlainObject returns true for empty objects in IE < 9
• Ensured _.max & _.min chain correctly
• Ensured clearTimeout use doesn’t cause errors in Titanium
• Ensured that the --stdout build option doesn’t write to a file
• Exposed memoized function’s cache
• Fixed Error.prototype iteration bugs
• Fixed “scripts” paths in component.json
• Made methods support customizing _.indexOf
• Made the build track dependencies of private functions
• Made the template pre-compiler build option avoid escaping non-ascii characters
• Made _.createCallback avoid binding functions if they don’t reference this
• Optimized the Closure Compiler minification process
• Optimized the large array cache for _.difference, _.intersection, & _.uniq
• Optimized internal _.flatten & _.indexOf use
• Reduced _.unzip & _.zip
• Removed special handling of arrays in _.assign & _.defaults

_v1.2.1

Apr. 29, 2013 — Diff — Docs

• Added Component package support
• Updated the build utility to work with changes in GitHub’s API
• Ensured _.isPlainObject works with objects created by Object.create(null)
• Ensured “isType” methods return false for subclassed values
• Ensured debounced functions, with leading & trailing calls enabled, only perform trailing calls after they’re called more than once

_v1.2.0

Apr. 16, 2013 — Diff — Docs

• Added _.unzip
• Added an options param to _.debounce & _.throttle
• Enabled non-underscore builds to include _.findWhere & _.chain
• Ensured “Array” & “Object” methods work with arguments objects & arrays respectively
• Ensured build utility runs on Windows
• Ensured underscore build versions of “isType” methods align with Underscore
• Ensured methods avoid issues with the __proto__ property
• Ensured _.isEqual uses a callback only if it’s a function
• Ensured _.merge applies a callback to nested properties
• Ensured _.merge provides the correct callback arguments when comparing objects
• Made lodash work with Browserify
• Removed all method compilation from the modern build

_v1.1.1

Mar. 27, 2013 — Diff — Docs

• Ensured the underscore build of _.forEach accepts a thisArg param
• Updated vendor/tar to work with Node.js v0.10

_v1.1.0

Mar. 26, 2013 — Diff — Docs

• Added _.createCallback, _.findIndex, _.findKey, _.parseInt, & _.runInContext
• Added _.support
• Added callback & thisArg params to _.flatten
• Added rhino -require support
• Added CommonJS/Node.js support to precompiled templates
• Ensured the exports object is not a DOM element
• Ensured _.isPlainObject returns false for objects without a [[Class]] of “Object”
• Made callback support in _.cloneDeep more closely follow its documentation
• Made _.object an alias of _.zipObject
• Made the template precompiler create missing directories of --output paths
• Optimized method chaining, object iteration, _.find, & _.pluck
• Updated backbone build method dependencies

_v1.0.2

Feb. 18, 2013 — Diff — Docs

• Ensured _.isPlainObject works when built-in Object.getPrototypeOf is unavailable

_v1.0.1

Feb. 18, 2013 — Diff — Docs

• Added support for specifying source map URLs in -p/--source-map options
• Ensured the second argument to _.assign is not treated as a callback
• Ensured -p/--source-map build options correctly set the sourceMappingURL
• Made -p/--source-map set source map “sources” keys based on the build
• Made _.defer use setImmediate, in Node.js, when available
• Made _.where search arrays for values regardless of their index position
• Removed dead code from _.template

_v1.0.0

Feb. 14, 2013 — Diff — Docs

Compatibility Warnings

• Made _.defaults preserve null values, instead of overwriting them

Changes

• Added _.at & _.partialRight
• Added modern & -p/--source-map build options
• Added “imports” option to _.templateSettings
• Added support for _.pluck & _.where callback shorthands
• Ensured _.assign & _.defaults support arrays
• Ensured _.merge assigns null values & produces dense arrays
• Deferred minifier downloads until the lodash utility requires them
• Flipped noNodeClass test to avoid Firebug’s “break on all errors” feature
• Made _.where support deep object comparisons
• Optimized _.invert, _.pairs, & _.values
• Reduced _.max, _.min, _.pluck, _.toArray, & _.where
• Removed support for automatic with-statement removal from _.template
• Simplified createIterator & iteratorTemplate
• Tweaked _.uniqueId to avoid problems with buggy minifiers
• Updated underscore build compatibility to v1.4.4
• Added callback & thisArg params to _.assign, _.clone, _.cloneDeep, _.first, _.last, _.initial, _.isEqual, _.merge, & _.rest

_v1.0.0-rc.3

Dec. 17, 2012 — Diff — Docs

Compatibility Warnings

• Made _#join, _#pop, & _#shift wrapper methods return unwrapped values
• Made “Function” methods wrapper counterparts return wrapped values
• Removed “chain” methods

Changes

• Added _.cloneDeep
• Added _.once to the backbone build
• Ensured backbone builds implement Underscore’s chaining behavior
• Ensured the settings=… build option doesn’t clobber the default moduleId
• Ensured lodash’s npm package works when packages aren’t globally installed
• Made compiled templates exported for AMD use the lodash module for _
• Removed the _.forEach dependency from _.intersection
• Optimized _.isArray & _.isFunction fallbacks as well as _.intersection, _.isDate, _.isRegExp, _.reduce, _.reduceRight, _.union, & _.uniq

_v1.0.0-rc.2

Dec. 5, 2012 — Diff — Docs

• Specified more method chaining behaviors
• Updated underscore build compatibility to v1.4.3

_v1.0.0-rc.1

Dec. 4, 2012 — Diff — Docs

Compatibility Warnings

• Added support for arguments objects to _.clone
• Ensured _.clone creates plain object clones of non-plain objects
• Made _(…) chain automatically without needing to call _#chain
• Made _.isEqual equate arguments objects to similar Object objects

Changes

• Ensure lodash runs in the JS engine embedded in Adobe products
• Ensured _.reduce & _.reduceRight provide the correct callback arguments
• Ensured _.throttle nulls the timeoutId
• Made deep _.clone more closely follow the structured clone algorithm
• Optimized compiled templates in Firefox
• Optimized _.forEach, _.forOwn, _.isNumber, & _.isString
• Simplified iteratorTemplate

_v0.10.0

Nov. 17, 2012 — Diff — Docs

Compatibility Warnings

• Renamed _.lateBind to _.bindKey
• Made _.defaults & _.extend iterate only own properties of source objects to align with Object.assign

Changes

• Added the build commands used to custom build copyright/license headers
• Added _.assign
• Ensured the underscore build of _.find returns the first match, not last
• Ensured _.defaults, _.extends, & _.merge work with _.reduce
• Made lodash’s npm package installation work with more system configurations
• Made _.extend an alias of _.assign
• Optimized _.contains, _.defaults, _.extend, & _.filter
• Restricted _.where to iterate only own properties of source objects
• Updated backbone build lodash method dependencies

_v0.9.2

Nov. 9, 2012 — Diff — Docs

• Added fromIndex param to _.contains
• Added moduleId build option
• Added Closure Compiler “simple” optimizations to the build process
• Added support for strings in _.max & _.min
• Added support for ES2015 template delimiters to _.template
• Ensured re-minification of lodash by third parties avoids Closure Compiler bugs
• Optimized _.every, _.find, _.some, & _.uniq

_v0.9.1

Oct. 31, 2012 — Diff — Docs

• Ensured _.every returns false as soon as the callback result is falsey
• Ensured _.isFinite returns false for non-numeric values
• Removed _.forEach chainability in the underscore build
• Simplified _.union

_v0.9.0

Oct. 24, 2012 — Diff — Docs

• Added a sourceURL option to _.template
• Ensured _.where returns an empty array if given an empty properties object
• Expanded _.isFinite to return true for numeric strings
• Reduced _.intersection, _.omit, _.pick, _.sortedIndex, & _.where
• Reduced the npm package size by only downloading minifiers for global installs
• Reduced lodash’s file size
• Improved source code comprehension by removing compilation from _.bindAll, _.contains, _.countBy, _.every, _.filter, _.find, _.functions, _.groupBy, _.invert, _.invoke, _.isEmpty, _.map, _.merge, _.omit, _.pairs, _.pick, _.pluck, _.reduce, _.reject, _.some, _.sortBy, _.values, _.where, & internal shimKeys

_v0.8.2

Oct. 10, 2012 — Diff — Docs

• Ensured _.map returns an array when given a falsey collection
• Ensured _.throttle clears its timeout when func is called
• Made _.max, _.min, _.shuffle support iterating objects
• Reduced createIterator, _.clone, _.compact
• Re-optimized _.max, _.min, & _.sortedIndex

_v0.8.1

Oct. 4, 2012 — Diff — Docs

• Enabled deep clone support in the underscore build when clone is explicitly included
• Reverted removal of first argument falsey checks from methods

_v0.8.0

Oct. 1, 2012 — Diff — Docs

Compatibility Warnings

• Made _.random return 0 or 1 when no arguments are given
• Moved late bind functionality from _.bind to _.lateBind
• Removed first argument falsey checks from methods
• Removed support for custom clone, isEqual, toArray methods from _.clone, _.isEqual, & _.toArray

Changes

• Added -d/--debug, -m/--minify, minus, plus, settings, & template build options
• Added _.isPlainObject & _.lateBind
• Enabled _.sortedIndex to accept a property name as the callback param
• Ensured methods accept a thisArg of null
• Fixed the iife build option to accept more values
• Made _.times return an array of callback results
• Simplified _.max, _.min, & _.reduceRight

_v0.7.0

Sept. 11, 2012 — Diff — Docs

Compatibility Warnings

• Renamed _.zipObject to _.object
• Replaced _.drop with _.omit
• Made _.drop an alias of _.rest

Changes

• Added _.invert, _.pairs, & _.random
• Added _.result to the backbone build
• Added exports, iife, -c/--stdout, -o/--output, & -s/--silent build options
• Ensured isPlainObject works with objects from other documents
• Ensured _.isEqual compares values with circular references correctly
• Ensured _.merge work with four or more arguments
• Ensured _.sortBy performs a stable sort for undefined values
• Ensured _.template works with “interpolate” delimiters containing ternary operators
• Ensured the production build works in Node.js
• Ensured template delimiters are tokenized correctly
• Made pseudo private properties _chain & _wrapped double-underscored to avoid conflicts
• Made minify.js support underscore.js
• Reduced the size of mobile & underscore builds
• Simplified _.isEqual & _.size

_v0.6.1

Aug. 29, 2012 — Diff — Docs

• Ensured IE conditional compilation isn’t enabled by the useSourceURL test
• Optimized isPlainObject

_v0.6.0

Aug. 28, 2012 — Diff — Docs

• Added callback & thisArg params to _.drop & _.pick
• Added hasObjectSpliceBug test to avoid delete operator use
• Added _.unescape
• Ensured _.reduce works with string objects in IE < 9
• Made _.omit an alias of _.drop
• Made compiled methods take advantage of engines with strict mode optimizations
• Optimized _.intersection & removed its dependency on _.every
• Reduced the file size of the underscore build

_v0.5.2

Aug. 21, 2012 — Diff — Docs

• Ensured _.isElement uses strict equality for its duck type check
• Ensured _.isObject returns a boolean value
• Ensured _.template & “Object” methods don’t error when given falsey values
• Made _.template generate less unused code in compiled templates

_v0.5.1

Aug. 18, 2012 — Diff — Docs

• Ensured _.bind correctly appends array arguments to partially applied arguments in older browsers

_v0.5.0

Aug. 17, 2012 — Diff — Docs

• Added _.countBy, _.drop, _.merge, & _.where
• Added csp (Content Security Policy) & underscore build options
• Added deep cloning support to _.clone
• Added Jam package support
• Added support for exiting early in _.forEach, _.forIn, & _.forOwn
• Added support for jQuery/MooTools DOM query collections to _.isEmpty & _.size
• Ensured development build works with IE conditional compilation enabled
• Ensured _.clone doesn’t clone arguments objects, DOM nodes, functions, or non-plain objects
• Ensured _.filter’s callback can’t modify result values
• Ensured _.isEmpty, _.isEquals, & _.size support arguments objects
• Ensured _.isEqual doesn’t inspect DOM nodes, works with objects from other documents, & calls custom isEqual methods before checking strict equality
• Ensured _.once frees the given function for garbage collection
• Ensured _.sortBy performs a stable sort
• Ensured reEvaluateDelimiter is used when _.templateSettings.evaluate is undefined
• Made _.range coerce arguments to numbers
• Optimized _.isFunction

_v0.4.2

July 16, 2012 — Diff — Docs

• Added strict build option
• Ensured _.bindAll, _.defaults, & _.extend avoid strict mode errors on read-only properties
• Optimized the iteration of large arrays in _.difference, _.intersection, & _.without
• Fixed build bugs related to removing variables

_v0.4.1

July 11, 2012 — Diff — Docs

• Fixed _.template regression
• Optimized build process to detect & remove more unused variables

_v0.4.0

July 11, 2012 — Diff — Docs

• Added bin & scripts entries to package.json
• Added legacy build option
• Added cross-browser support for strings to “Collection” methods
• Added _.zipObject
• Leveraged _.indexOf’s fromIndex in _.difference & _.without
• Optimized compiled templates
• Optimized inlining the iteratorTemplate for builds
• Optimized object iteration for “Collection” methods
• Optimized partially applied _.bind in V8
• Made compiled templates more debuggable
• Made _.size work with falsey values & consistent cross-browser with arguments objects
• Moved _.groupBy & _.sortBy back to the “Collection” category
• Removed arguments object from _.range

_v0.3.2

June 14, 2012 — Diff — Docs

• Ensured _.escape returns an empty string for nullish values
• Ensured sourceURL support doesn’t cause errors in Adobe’s JS engine
• Fixed regression in generating custom builds
• Moved _.invoke & _.pluck back to the “Collection” category
• Moved _.tap to the “Seq” category

_v0.3.1

June 10, 2012 — Diff — Docs

• Added backbone build option
• Ensured “Array” methods allow falsey array params
• Removed _.isArguments fallback from the mobile build
• Simplified _.pluck, _.values & _(...) method wrappers

_v0.3.0

June 6, 2012 — Diff — Docs

• Added _.forIn & _.forOwn
• Added category build option
• Added fromIndex param to _.indexOf & _.lastIndexOf
• Added //@ sourceURL support to _.template
• Added thisArg param to _.sortedIndex & _.uniq
• Ensured array-like objects with invalid length properties are treated like regular objects
• Ensured _.sortedIndex supports arrays with high length values
• Fixed prototype iteration bug in _.keys
• Optimized _.times & this bindings in iterator methods

_v0.2.2

May 30, 2012 — Diff — Docs

• Added mobile build option
• Ensured _.find returns undefined for unmatched values
• Ensured _.templateSettings.variable is compatible with Underscore
• Optimized _.escape
• Reduced dependencies of _.find

_v0.2.1

May 24, 2012 — Diff — Docs

• Adjusted the lodash export order for r.js
• Ensured _.groupBy values are added to own, not inherited, properties
• Made _.bind follow ES5 spec to support a popular Backbone.js pattern
• Removed the alias _.intersect
• Simplified _.bind, _.flatten, _.groupBy, _.max, & _.min

_v0.2.0

May 21, 2012 — Diff — Docs

• Added _.partial
• Added thisArg param to _.groupBy
• Added “lazy bind” support to _.bind
• Added custom build options
• Added default _.templateSettings.variable value
• Added native method overwrite detection to avoid bad native shims
• Added support for more AMD build optimizers & aliasing as the “underscore” module
• Added whitespace to compiled strings
• Commented the iterationFactory options object
• Ensured _(...) returns given wrapper instances
• Ensured _.max & _.min support extremely large arrays
• Ensured _.throttle works in tight loops
• Fixed clearTimeout typo
• Fixed [DontEnum] bug in IE < 9
• Fixed prototype iteration bug in Firefox < 3.6, Opera < 11.60, & Safari < 5.1
• Inlined _.isFunction calls
• Made _.debounce’ed functions match _.throttle’ed functions’ return value behavior
• Made _.escape no longer translate the “>” character
• Simplified all “Array” methods
• Optimized _.debounce, _.escape, _.flatten, _.forEach, _.groupBy, _.intersection, _.invoke, _.isObject, _.max, _.min, _.pick, _.shuffle, _.sortedIndex, _.template, _.throttle, _.union, _.uniq

_v0.1.0

Apr. 23, 2012 — Docs

• Initial release