webpack/lib/performance/hasOnlyUnusedExports.js

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.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Alexander Akait @alexander-akait
*/

"use strict";

const { UsageState } = require("../ExportsInfo");

/** @import ChunkGraph from "../ChunkGraph" */
/** @import Module from "../Module" */
/** @import ModuleGraph from "../ModuleGraph" */

/**
 * Tells whether a module provides exports and no runtime uses any of them.
 * One exporting nothing is there for its side effects, a different mistake.
 * @param {Module} module the module to look up
 * @param {ModuleGraph} moduleGraph the module graph
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @returns {boolean} true when it provides exports and none are used
 */
const hasOnlyUnusedExports = (module, moduleGraph, chunkGraph) => {
	const runtimes = [...chunkGraph.getModuleRuntimes(module)];
	let provided = 0;

	for (const exportInfo of moduleGraph.getExportsInfo(module).exports) {
		if (!exportInfo.provided) continue;

		provided++;

		for (const runtime of runtimes) {
			// `NoInfo` included: unknown usage is not unused.
			if (exportInfo.getUsed(runtime) !== UsageState.Unused) return false;
		}
	}

	return provided > 0;
};

module.exports = hasOnlyUnusedExports;