mirror of https://github.com/webpack/webpack.git
98 lines
2.8 KiB
JavaScript
98 lines
2.8 KiB
JavaScript
/*
|
|
MIT License http://www.opensource.org/licenses/mit-license.php
|
|
Author Tobias Koppers @sokra
|
|
*/
|
|
"use strict";
|
|
|
|
const addToSet = (a, b) => {
|
|
for(const item of b) {
|
|
if(!a.includes(item))
|
|
a.push(item);
|
|
}
|
|
return a;
|
|
};
|
|
|
|
const isSubset = (biggerSet, subset) => {
|
|
if(biggerSet === true) return true;
|
|
if(subset === true) return false;
|
|
return subset.every(item => biggerSet.indexOf(item) >= 0);
|
|
};
|
|
|
|
class FlagDependencyUsagePlugin {
|
|
apply(compiler) {
|
|
compiler.hooks.compilation.tap("FlagDependencyUsagePlugin", (compilation) => {
|
|
compilation.hooks.optimizeModulesAdvanced.tap("FlagDependencyUsagePlugin", (modules) => {
|
|
|
|
const processModule = (module, usedExports) => {
|
|
module.used = true;
|
|
if(module.usedExports === true)
|
|
return;
|
|
else if(usedExports === true)
|
|
module.usedExports = true;
|
|
else if(Array.isArray(usedExports)) {
|
|
const old = module.usedExports ? module.usedExports.length : -1;
|
|
module.usedExports = addToSet(module.usedExports || [], usedExports);
|
|
if(module.usedExports.length === old)
|
|
return;
|
|
} else if(Array.isArray(module.usedExports))
|
|
return;
|
|
else
|
|
module.usedExports = false;
|
|
|
|
// 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
|
|
if(module.factoryMeta.sideEffectFree) {
|
|
if(module.usedExports === false) return;
|
|
if(Array.isArray(module.usedExports) && module.usedExports.length === 0) return;
|
|
}
|
|
|
|
queue.push([module, module.usedExports]);
|
|
};
|
|
|
|
const processDependenciesBlock = (depBlock, usedExports) => {
|
|
for(const dep of depBlock.dependencies) {
|
|
processDependency(dep);
|
|
}
|
|
for(const variable of depBlock.variables) {
|
|
for(const dep of variable.dependencies) {
|
|
processDependency(dep);
|
|
}
|
|
}
|
|
for(const block of depBlock.blocks) {
|
|
queue.push([block, usedExports]);
|
|
}
|
|
};
|
|
|
|
const processDependency = dep => {
|
|
const reference = dep.getReference && dep.getReference();
|
|
if(!reference) return;
|
|
const module = reference.module;
|
|
const importedNames = reference.importedNames;
|
|
const oldUsed = module.used;
|
|
const oldUsedExports = module.usedExports;
|
|
if(!oldUsed || (importedNames && (!oldUsedExports || !isSubset(oldUsedExports, importedNames)))) {
|
|
processModule(module, importedNames);
|
|
}
|
|
};
|
|
|
|
for(const module of modules) {
|
|
module.used = false;
|
|
}
|
|
|
|
const queue = [];
|
|
for(const chunk of compilation.chunks) {
|
|
if(chunk.entryModule) {
|
|
processModule(chunk.entryModule, true);
|
|
}
|
|
}
|
|
|
|
while(queue.length) {
|
|
const queueItem = queue.pop();
|
|
processDependenciesBlock(queueItem[0], queueItem[1]);
|
|
}
|
|
});
|
|
});
|
|
}
|
|
}
|
|
module.exports = FlagDependencyUsagePlugin;
|