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@sokra sokra released this 25 Feb 02:44
· 11229 commits to main since this release
v4.0.0
213226e

Big changes

  • Environment
    • Node.js 4 is no longer supported. Source Code was upgraded to a higher ecmascript version.
  • Usage
    • You have to choose (mode or --mode) between two modes now: production or development
      • production enables all kind of optimizations to generate optimized bundles
      • development enables comments and hint for development and enables the eval devtool
      • production doesn't support watching, development is optimized for fast incremental rebuilds
      • production also enables module concatenating (Scope Hoisting)
      • You can configure this in detail with the flags in optimization.* (build your custom mode)
      • process.env.NODE_ENV are set to production or development (only in built code, not in config)
      • There is a hidden none mode which disables everything
  • Syntax
    • import() always returns a namespace object. CommonJS modules are wrapped into the default export
      • This probably breaks your code, if you used to import CommonJs with import()
  • Configuration
    • You no longer need to use these plugins:
      • NoEmitOnErrorsPlugin -> optimization.noEmitOnErrors (on by default in production mode)
      • ModuleConcatenationPlugin -> optimization.concatenateModules (on by default in production mode)
      • NamedModulesPlugin -> optimization.namedModules (on by default in develoment mode)
    • CommonsChunkPlugin was removed -> optimization.splitChunks, optimization.runtimeChunk
  • JSON
    • webpack now handles JSON natively
      • You may need to add type: "javascript/auto" when transforming JSON via loader to JS
      • Just using JSON without loader should still work
    • allows to import JSON via ESM syntax
      • unused exports elimination for JSON modules
  • Optimization
    • Upgrade uglifyjs-webpack-plugin to v1
      • ES15 support

Big features

  • Modules
    • webpack now supports these module types:
      • javascript/auto: (The default one in webpack 3) Javascript module with all module systems enabled: CommonJS, AMD, ESM
      • javascript/esm: EcmaScript modules, all other module system are not available
      • javascript/dynamic: Only CommonJS and, EcmaScript modules are not available
      • json: JSON data, it's available via require and import
      • webassembly/experimental: WebAssembly modules (currently experimental)
    • javascript/esm handles ESM more strictly compared to javascript/auto:
      • Imported names need to exist on imported module
      • Dynamic modules (non-esm, i. e. CommonJs) can only imported via default import, everything else (including namespace import) emit errors
    • In .mjs modules are javascript/esm by default
    • WebAssembly modules
      • can import other modules (JS and WASM)
      • Exports from WebAssembly modules are validated by ESM import
        • You'll get a warning/error when trying to import a non-existing export from WASM
      • can only be used in async chunks. They doesn't work in initial chunks (would be bad for web performance)
        • Import modules using WASM via import()
      • This is an experimental feature and subject of change
  • Optimization
    • sideEffects: false is now supported in package.json
      • sideEffects in package.json also supports glob expressions and arrays of glob expressions
    • Instead of a JSONP function a JSONP array is used -> async script tag support, order no longer matter
    • New optimization.splitChunks option was introduced
      Details: https://gist.github.com/sokra/1522d586b8e5c0f5072d7565c2bee693
    • Dead branches are now removed by webpack itself
      • Before: Uglify removed the dead code
      • Now: webpack removes the dead code (in some cases)
      • This prevents crashing when import() occur in a dead branch
  • Syntax
    • webpackInclude and webpackExclude are supported by the magic comment for import(). They allow to filter files when using a dynamic expression.
    • Using System.import() now emits a warning
      • You can disable the warning with Rule.parser.system: true
      • You can disable System.import with Rule.parser.system: false
  • Configuration
    • Resolving can now be configured with module.rules[].resolve. It's merged with the global configuration.
    • optimization.minimize has been added to switch minimizing on/off
      • By default: on in production mode, off in development mode
    • optimization.minimizer has been added to configurate minimizers and options
  • Usage
    • Some Plugin options are now validated
    • CLI has been move to webpack-cli, you need to install webpack-cli to use the CLI
    • The ProgressPlugin (--progress) now displays plugin names
      • At least for plugins migrated to the new plugin system
  • Performance
    • UglifyJs now caches and parallizes by default
    • Multiple performance improvements, especially for faster incremental rebuilds
    • performance improvement for RemoveParentModulesPlugin
  • Stats
    • Stats can display modules nested in concatenated modules

Features

  • Configuration
    • Module type is automatically choosen for mjs, json and wasm extensions. Other extensions need to be configured via module.rules[].type
    • Incorrect options.dependencies configurations now throw error
    • sideEffects can be overriden via module.rules
    • output.hashFunction can now be a Constructor to a custom hash function
      • You can provide a non-cryto hash function for performance reasons
    • add output.globalObject config option to allow to choose the global object reference in runtime exitCode
  • Runtime
    • Error for chunk loading now includes more information and two new properties type and request.
  • Devtool
    • remove comment footer from SourceMaps and eval
    • add support for include test and exclude to the eval source map devtool plugin
  • Performance
    • webpacks AST can be passed directly from loader to webpack to avoid extra parsing
    • Unused modules are no longer unnecessarly concatenated
    • Add a ProfilingPlugin which write a (Chrome) profile file which includes timings of plugins
    • Migrate to using for of instead of forEach
    • Migrate to using Map and Set instead of Objects
    • Migrate to using includes instead of indexOf
    • Replaced some RegExp with string methods
    • Queue don't enqueues the same job twice
    • Use faster md4 hash for hashing by default
  • Optimization
    • When using more than 25 exports mangled export names are shorter.
    • script tags are no longer text/javascript and async as this are the default values (saves a few bytes)
    • The concatenated module now generates a bit less code
    • constant replacements now don't need __webpack_require__ and argument is omitted
  • Defaults
    • webpack now looks for the .wasm, .mjs, .js and .json extensions in this order
    • output.pathinfo is now on by default in develoment mode
    • in-memory caching is now off by default in production
    • entry defaults to ./src
    • output.path defaults to ./dist
    • Use production defaults when omiting the mode option
  • Usage
    • Add detailed progress reporting to SourceMapDevToolPlugin
    • removed plugins now give a useful error message
  • Stats
    • Sizes are now shown in kiB instead of kB in Stats
    • entrypoints are now shows by default in Stats
    • chunks now display <{parents}> >{children}< and ={siblings}= in Stats
    • add buildAt time to stats
    • stats json now includes the output path
  • Syntax
    • A resource query is supported in context
    • Referencing entry point name in import() now emits a error instead of a warning
    • Upgraded to acorn 5 and support ES 2018
  • Plugins
    • done is now an async hook

Bugfixes

  • Generated comments no longer break on */
  • webpack no longer modifies the passed options object
  • Compiler "watch-run" hook now has the Compiler as first parameter
  • add output.chunkCallbackName to the schema to allow configurating WebWorker template
  • Using module.id/loaded now correctly bails out of Module Concatentation (Scope Hoisting)
  • OccurenceOrderPlugin now sorts modules in correct order (instead of reversed)
  • timestamps for files are read from watcher when calling Watching.invalidate
  • fix incorrect -! behavior with post loaders
  • add run and watchRun hooks for MultiCompiler
  • this is now undefined in ESM
  • VariableDeclaration are correctly identified as var, const or let
  • Parser now parse the source code with the correct source type (module/script) when the module type javascript/dynamic or javascript/module is used.
  • don't crash on missing modules with buildMeta of null
  • add original-fs module for electron targets
  • HMRPlugin can be added to the Compiler outside of plugins

Internal changes

  • Replaced plugin calls with tap calls (new plugin system)
  • Migrated many deprecated plugins to new plugin system API
  • added buildMeta.exportsType: "default" for json modules
  • Remove unused methods from Parser (parserStringArray, parserCalculatedStringArray)
  • Remove ability to clear BasicEvaluatedExpression and to have multiple types
  • Buffer.from instead of new Buffer
  • Avoid using forEach and use for of instead
  • Use neo-async instead of async
  • Update tapable and enhanced-resolve dependencies to new major versions
  • Use prettier

Removed features

  • removed module.loaders
  • removed loaderContext.options
  • removed Compilation.notCacheable flag
  • removed NoErrorsPlugin
  • removed Dependency.isEqualResource
  • removed NewWatchingPlugin
  • removed CommonsChunkPlugin

Breaking changes for plugins/loaders

  • new plugin system
    • plugin method is backward-compatible
    • Plugins should use Compiler.hooks.xxx.tap(<plugin name>, fn) now
  • New major version of enhanced-resolve
  • Templates for chunks may now generate multiple assets
  • Chunk.chunks/parents/blocks are no longer Arrays. A Set is used internally and there are methods to access it.
  • Parser.scope.renames and Parser.scope.definitions are no longer Objects/Arrays, but Map/Sets.
  • Parser uses StackedSetMap (LevelDB-like datastructure) instead of Arrays
  • Compiler.options is no longer set while applying plugins
  • Harmony Dependencies has changed because of refactoring
  • Dependency.getReference() may now return a weak property. Dependency.weak is now used by the Dependency base class and returned in the base impl of getReference()
  • Constructor arguments changed for all Modules
  • Merged options into options object for ContextModule and resolveDependencies
  • Changed and renamed dependencies for `import()
  • Moved Compiler.resolvers into Compiler.resolverFactory accessible with plugins
  • Dependency.isEqualResource has been replaced with Dependency.getResourceIdentifier
  • Methods on Template are now static
  • A new RuntimeTemplate class has been added and outputOptions and requestShortener has been moved to this class
    • Many methods has been updated to use the RuntimeTemplate instead
    • We plan to move code which accesses the runtime to this new class
  • Module.meta has been replaced with Module.buildMeta
  • Module.buildInfo and Module.factoryMeta have been added
  • Some properties of Module have been moved into the new objects
  • added loaderContext.rootContext which points to the context options. Loaders may use it to make stuff relative to the application root.
  • add this.hot flag to loader context when HMR is enabled
  • buildMeta.harmony has been replaced with buildMeta.exportsType: "namespace
  • The chunk graph has changed:
    • Before: Chunks were connected with parent-child-relationships.
    • Now: ChunkGroups are connected with parent-child-relationships. ChunkGroups contain Chunks in order.
    • Before: AsyncDependenciesBlocks reference a list of Chunks in order.
    • Now: AsyncDependenciesBlocks reference a single ChunkGroup.
  • file/contextTimestamps are Maps now
  • map/foreach Chunks/Modules/Parents methods are now deprecated/removed
  • NormalModule accept options object in Constructor
  • Added required generator argument for NormalModule
  • Added createGenerator and generator hooks for NormalModuleFactory to customize code generation
  • Allow to customize render manifest for Chunks via hooks
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