Reduss

A passionate love letter to Array.prototype.reduce()

Functions

atPathSet(path, data, [baseObject]) ⇒ Object

leafs(obj, [previousPath]) ⇒ Array.<PathValueObject>

mapKeys(mappers, objectToMap) ⇒ Object

mapKeysDeep(mappers, objectToMap) ⇒ Object

path(path, objToAccess) ⇒ *

pickIndexes(indexes, arrayOfElements) ⇒ Array.<*>

reduceIf(condition, reducer, array, [initAcc]) ⇒ *

sumOnly(condition, numbers) ⇒ number

atPathSet(path, data, [baseObject]) ⇒ Object

Kind: global function
Returns: Object - A new object with the path provided equal to data, and optionnaly any values present in baseObject

Param	Type	Default	Description
path	string		The path on which to set a new value
data	*		The data to set
[baseObject]	Object	Object	The base object, serve as the initial accumulator, default {}

Example

//returns { some: { prop: { one: 1, two: 2 } } }
atPathSet('some.prop.one', 1, atPathSet('some.prop.two', 2))

leafs(obj, [previousPath]) ⇒ Array.<PathValueObject>

Kind: global function
Returns: Array.<PathValueObject> - An array with object containing the leafs information (path/value)

Param	Type	Default	Description
obj	object		The object on which the leafs are selected
[previousPath]	array	array	The accumulated path while iterating on obj properties, default to empty array, needed only for recursion, should not be a passed argument when calling the function

Example

// returns [
//   { path: ['a', 'b', 'c'], value: 4 },
//   { path: ['a', 'b', 'e'], value: 6 },
//   { path: ['a', 'd', 'l'], value: 2 }
// ]
leafs({
    a: {
      b: { c: 4, e: 6 },
      d: { l: 2 }
    }
  })

mapKeys(mappers, objectToMap) ⇒ Object

Kind: global function
Returns: Object - A new object with the mapped keys

Param	Type	Description
mappers	Object.<string, function()>	Object with keys corresponding to paths and value corresponding to maping function taking the value at objectToMap path
objectToMap	Object	The source object for the mapping

Example

// returns { str: 'SOMEVALUE', num: 4 }
mapKeys(
   { str: x => x.toUpperCase(), num: n => n + 3 },
   { str: 'someValue',
     num: 1,
   }
)

mapKeysDeep(mappers, objectToMap) ⇒ Object

Kind: global function
Returns: Object - A new object with the mapped paths

Param	Type	Description
mappers	Object.<string, function()>	Object with keys corresponding to paths (or simple keys) and value corresponding to maping function taking the value at objectToMap path
objectToMap	Object	The source object for the mapping

Example

// returns {
// obj: {
//     prop: {
//        last: 8
//      }
//    }
// }
mapKeysDeep(
   {
     'obj.prop.last': x => x * 2
   },
   {
     obj: {
       prop: { last: 4 }
     }
   }
 )

path(path, objToAccess) ⇒ *

Kind: global function
Returns: * - The value corresponding to the path
Throws:

• If we try to access a non existing property on objToAccess

Param	Type	Description
path	string	A string representing the path to access (e.g. 'some.prop.nested')
objToAccess	Object	The accessed object

Example

// returns 6
path('a.b.c', { a: { b: { c: 6 } } })

pickIndexes(indexes, arrayOfElements) ⇒ Array.<*>

Kind: global function
Returns: Array.<*> - The picked elements in the order of the indexes argument
Throws:

• Can throw an error if oyu try to pick an index which does not exist on arrayOfElements

Param	Type	Description
indexes	Array.<number>	An array of indexes to pick (the order matter)
arrayOfElements	Array.<*>	The array to pick values from

Example

// returns [6, 6, 2]
pickIndexes([2, 4, 1], [1, 2, 6, 1, 6])

reduceIf(condition, reducer, array, [initAcc]) ⇒ *

Kind: global function
Returns: * - The reduced value

Param	Type	Default	Description
condition	function		Take as first argment the current value and next all the reducer argument (acumulator, index, array) and return true if the reducer should be called
reducer	function		Take all the reducer argument (acumulator, value, index, array), return the new accumuulator
array	Array		An array to reduce
[initAcc]	*	Array	The initial accumulator, default empty array

Example

// returns 6
reduceIf(x => x <= 3, (acc, v) => acc + v, [1,2,3,4], 0)

sumOnly(condition, numbers) ⇒ number

Kind: global function
Returns: number - The sum of matching numbers

Param	Type	Description
condition	function	Retun true if the number can be summed
numbers	Array.<number>	The array of numbers to sum

Example

// returns 6
sumOnly(x => x <= 3, [1,2,3,4])