webpack/lib/optimize/MangleExportsPlugin.js

87 lines
2.2 KiB
JavaScript

/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const { numberToIdentifier } = require("../Template");
const { assignDeterministicIds } = require("../ids/IdHelpers");
const {
concatComparators,
compareSelect,
compareStringsNumeric
} = require("../util/comparators");
/** @typedef {import("../Compiler")} Compiler */
const canMangleSomething = exportsInfo => {
for (const exportInfo of exportsInfo.exports) {
if (exportInfo.canMangle === true) {
return true;
}
}
return false;
};
const comparator = concatComparators(
// Sort used before unused fields
compareSelect(e => e.used !== false, (a, b) => (a === b ? 0 : a ? -1 : 1)),
// Sort by name
compareSelect(e => e.name, compareStringsNumeric)
);
class MangleExportsPlugin {
/**
* @param {Compiler} compiler webpack compiler
* @returns {void}
*/
apply(compiler) {
compiler.hooks.compilation.tap("MangleExportsPlugin", compilation => {
const moduleGraph = compilation.moduleGraph;
compilation.hooks.optimizeCodeGeneration.tap(
"MangleExportsPlugin",
modules => {
for (const module of modules) {
const exportsInfo = moduleGraph.getExportsInfo(module);
if (!canMangleSomething(exportsInfo)) continue;
const usedNames = new Set();
const mangleableExports = [];
// Don't rename single char exports or exports that can't be mangled
for (const exportInfo of exportsInfo.exports) {
const name = exportInfo.name;
if (
exportInfo.canMangle !== true ||
(name.length === 1 || /^a-zA-Z_\$$/.test(name))
) {
exportInfo.usedName = name;
usedNames.add(name);
} else {
mangleableExports.push(exportInfo);
}
}
assignDeterministicIds(
mangleableExports,
e => e.name,
comparator,
(e, id) => {
const name = numberToIdentifier(id);
const size = usedNames.size;
usedNames.add(name);
if (size === usedNames.size) return false;
e.usedName = name;
return true;
},
[26, 52],
52,
usedNames.size
);
}
}
);
});
}
}
module.exports = MangleExportsPlugin;