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Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.
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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const Dependency = require("./Dependency");
const { UsageState } = require("./ExportsInfo");
const ModuleGraphConnection = require("./ModuleGraphConnection");
const { STAGE_DEFAULT } = require("./OptimizationStages");
const ArrayQueue = require("./util/ArrayQueue");
const TupleQueue = require("./util/TupleQueue");
const { getEntryRuntime, mergeRuntimeOwned } = require("./util/runtime");
/** @typedef {import("./Chunk")} Chunk */
/** @typedef {import("./ChunkGroup")} ChunkGroup */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./DependenciesBlock")} DependenciesBlock */
/** @typedef {import("./Dependency").ReferencedExport} ReferencedExport */
/** @typedef {import("./ExportsInfo")} ExportsInfo */
/** @typedef {import("./Module")} Module */
/** @typedef {import("./util/runtime").RuntimeSpec} RuntimeSpec */
const { NO_EXPORTS_REFERENCED, EXPORTS_OBJECT_REFERENCED } = Dependency;
const PLUGIN_NAME = "FlagDependencyUsagePlugin";
const PLUGIN_LOGGER_NAME = `webpack.${PLUGIN_NAME}`;
class FlagDependencyUsagePlugin {
/**
* @param {boolean} global do a global analysis instead of per runtime
*/
constructor(global) {
this.global = global;
}
/**
* Apply the plugin
* @param {Compiler} compiler the compiler instance
* @returns {void}
*/
apply(compiler) {
compiler.hooks.compilation.tap(PLUGIN_NAME, compilation => {
const moduleGraph = compilation.moduleGraph;
compilation.hooks.optimizeDependencies.tap(
{ name: PLUGIN_NAME, stage: STAGE_DEFAULT },
modules => {
if (compilation.moduleMemCaches) {
throw new Error(
"optimization.usedExports can't be used with cacheUnaffected as export usage is a global effect"
);
}
const logger = compilation.getLogger(PLUGIN_LOGGER_NAME);
/** @type {Map} */
const exportInfoToModuleMap = new Map();
/** @type {TupleQueue<[Module, RuntimeSpec]>} */
const queue = new TupleQueue();
/**
* @param {Module} module module to process
* @param {(string[] | ReferencedExport)[]} usedExports list of used exports
* @param {RuntimeSpec} runtime part of which runtime
* @param {boolean} forceSideEffects always apply side effects
* @returns {void}
*/
const processReferencedModule = (
module,
usedExports,
runtime,
forceSideEffects
) => {
const exportsInfo = moduleGraph.getExportsInfo(module);
if (usedExports.length > 0) {
if (!module.buildMeta || !module.buildMeta.exportsType) {
if (exportsInfo.setUsedWithoutInfo(runtime)) {
queue.enqueue(module, runtime);
}
return;
}
for (const usedExportInfo of usedExports) {
let usedExport;
let canMangle = true;
if (Array.isArray(usedExportInfo)) {
usedExport = usedExportInfo;
} else {
usedExport = usedExportInfo.name;
canMangle = usedExportInfo.canMangle !== false;
}
if (usedExport.length === 0) {
if (exportsInfo.setUsedInUnknownWay(runtime)) {
queue.enqueue(module, runtime);
}
} else {
let currentExportsInfo = exportsInfo;
for (let i = 0; i < usedExport.length; i++) {
const exportInfo = currentExportsInfo.getExportInfo(
usedExport[i]
);
if (canMangle === false) {
exportInfo.canMangleUse = false;
}
const lastOne = i === usedExport.length - 1;
if (!lastOne) {
const nestedInfo = exportInfo.getNestedExportsInfo();
if (nestedInfo) {
if (
exportInfo.setUsedConditionally(
used => used === UsageState.Unused,
UsageState.OnlyPropertiesUsed,
runtime
)
) {
const currentModule =
currentExportsInfo === exportsInfo
? module
: exportInfoToModuleMap.get(currentExportsInfo);
if (currentModule) {
queue.enqueue(currentModule, runtime);
}
}
currentExportsInfo = nestedInfo;
continue;
}
}
if (
exportInfo.setUsedConditionally(
v => v !== UsageState.Used,
UsageState.Used,
runtime
)
) {
const currentModule =
currentExportsInfo === exportsInfo
? module
: exportInfoToModuleMap.get(currentExportsInfo);
if (currentModule) {
queue.enqueue(currentModule, runtime);
}
}
break;
}
}
}
} else {
// for a module without side effects we stop tracking usage here when no export is used
// This module won't be evaluated in this case
// TODO webpack 6 remove this check
if (
!forceSideEffects &&
module.factoryMeta !== undefined &&
module.factoryMeta.sideEffectFree
) {
return;
}
if (exportsInfo.setUsedForSideEffectsOnly(runtime)) {
queue.enqueue(module, runtime);
}
}
};
/**
* @param {DependenciesBlock} module the module
* @param {RuntimeSpec} runtime part of which runtime
* @param {boolean} forceSideEffects always apply side effects
* @returns {void}
*/
const processModule = (module, runtime, forceSideEffects) => {
/** @type {Map>} */
const map = new Map();
/** @type {ArrayQueue} */
const queue = new ArrayQueue();
queue.enqueue(module);
for (;;) {
const block = queue.dequeue();
if (block === undefined) break;
for (const b of block.blocks) {
if (
!this.global &&
b.groupOptions &&
b.groupOptions.entryOptions
) {
processModule(
b,
b.groupOptions.entryOptions.runtime || undefined,
true
);
} else {
queue.enqueue(b);
}
}
for (const dep of block.dependencies) {
const connection = moduleGraph.getConnection(dep);
if (!connection || !connection.module) {
continue;
}
const activeState = connection.getActiveState(runtime);
if (activeState === false) continue;
const { module } = connection;
if (activeState === ModuleGraphConnection.TRANSITIVE_ONLY) {
processModule(module, runtime, false);
continue;
}
const oldReferencedExports = map.get(module);
if (oldReferencedExports === EXPORTS_OBJECT_REFERENCED) {
continue;
}
const referencedExports =
compilation.getDependencyReferencedExports(dep, runtime);
if (
oldReferencedExports === undefined ||
oldReferencedExports === NO_EXPORTS_REFERENCED ||
referencedExports === EXPORTS_OBJECT_REFERENCED
) {
map.set(module, referencedExports);
} else if (
oldReferencedExports !== undefined &&
referencedExports === NO_EXPORTS_REFERENCED
) {
continue;
} else {
let exportsMap;
if (Array.isArray(oldReferencedExports)) {
exportsMap = new Map();
for (const item of oldReferencedExports) {
if (Array.isArray(item)) {
exportsMap.set(item.join("\n"), item);
} else {
exportsMap.set(item.name.join("\n"), item);
}
}
map.set(module, exportsMap);
} else {
exportsMap = oldReferencedExports;
}
for (const item of referencedExports) {
if (Array.isArray(item)) {
const key = item.join("\n");
const oldItem = exportsMap.get(key);
if (oldItem === undefined) {
exportsMap.set(key, item);
}
// if oldItem is already an array we have to do nothing
// if oldItem is an ReferencedExport object, we don't have to do anything
// as canMangle defaults to true for arrays
} else {
const key = item.name.join("\n");
const oldItem = exportsMap.get(key);
if (oldItem === undefined || Array.isArray(oldItem)) {
exportsMap.set(key, item);
} else {
exportsMap.set(key, {
name: item.name,
canMangle: item.canMangle && oldItem.canMangle
});
}
}
}
}
}
}
for (const [module, referencedExports] of map) {
if (Array.isArray(referencedExports)) {
processReferencedModule(
module,
referencedExports,
runtime,
forceSideEffects
);
} else {
processReferencedModule(
module,
Array.from(referencedExports.values()),
runtime,
forceSideEffects
);
}
}
};
logger.time("initialize exports usage");
for (const module of modules) {
const exportsInfo = moduleGraph.getExportsInfo(module);
exportInfoToModuleMap.set(exportsInfo, module);
exportsInfo.setHasUseInfo();
}
logger.timeEnd("initialize exports usage");
logger.time("trace exports usage in graph");
/**
* @param {Dependency} dep dependency
* @param {RuntimeSpec} runtime runtime
*/
const processEntryDependency = (dep, runtime) => {
const module = moduleGraph.getModule(dep);
if (module) {
processReferencedModule(
module,
NO_EXPORTS_REFERENCED,
runtime,
true
);
}
};
/** @type {RuntimeSpec} */
let globalRuntime = undefined;
for (const [
entryName,
{ dependencies: deps, includeDependencies: includeDeps, options }
] of compilation.entries) {
const runtime = this.global
? undefined
: getEntryRuntime(compilation, entryName, options);
for (const dep of deps) {
processEntryDependency(dep, runtime);
}
for (const dep of includeDeps) {
processEntryDependency(dep, runtime);
}
globalRuntime = mergeRuntimeOwned(globalRuntime, runtime);
}
for (const dep of compilation.globalEntry.dependencies) {
processEntryDependency(dep, globalRuntime);
}
for (const dep of compilation.globalEntry.includeDependencies) {
processEntryDependency(dep, globalRuntime);
}
while (queue.length) {
const [module, runtime] = /** @type {[Module, RuntimeSpec]} */ (
queue.dequeue()
);
processModule(module, runtime, false);
}
logger.timeEnd("trace exports usage in graph");
}
);
});
}
}
module.exports = FlagDependencyUsagePlugin;