webpack/lib/dependencies/CommonJsSelfReferenceDependency.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 Tobias Koppers @sokra
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const { equals } = require("../util/ArrayHelpers");
const makeSerializable = require("../util/makeSerializable");
const propertyAccess = require("../util/propertyAccess");
const NullDependency = require("./NullDependency");

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").ExportsSpec} ExportsSpec */
/** @typedef {import("../Dependency").ReferencedExport} ReferencedExport */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../util/runtime").RuntimeSpec} RuntimeSpec */

class CommonJsSelfReferenceDependency extends NullDependency {
	constructor(range, base, names, call) {
		super();
		this.range = range;
		this.base = base;
		this.names = names;
		this.call = call;
	}

	get type() {
		return "cjs self exports reference";
	}

	get category() {
		return "self";
	}

	/**
	 * @returns {string | null} an identifier to merge equal requests
	 */
	getResourceIdentifier() {
		return `self`;
	}

	/**
	 * Returns list of exports referenced by this dependency
	 * @param {ModuleGraph} moduleGraph module graph
	 * @param {RuntimeSpec} runtime the runtime for which the module is analysed
	 * @returns {(string[] | ReferencedExport)[]} referenced exports
	 */
	getReferencedExports(moduleGraph, runtime) {
		return [this.call ? this.names.slice(0, -1) : this.names];
	}

	serialize(context) {
		const { write } = context;
		write(this.range);
		write(this.base);
		write(this.names);
		write(this.call);
		super.serialize(context);
	}

	deserialize(context) {
		const { read } = context;
		this.range = read();
		this.base = read();
		this.names = read();
		this.call = read();
		super.deserialize(context);
	}
}

makeSerializable(
	CommonJsSelfReferenceDependency,
	"webpack/lib/dependencies/CommonJsSelfReferenceDependency"
);

CommonJsSelfReferenceDependency.Template = class CommonJsSelfReferenceDependencyTemplate extends (
	NullDependency.Template
) {
	/**
	 * @param {Dependency} dependency the dependency for which the template should be applied
	 * @param {ReplaceSource} source the current replace source which can be modified
	 * @param {DependencyTemplateContext} templateContext the context object
	 * @returns {void}
	 */
	apply(
		dependency,
		source,
		{ module, moduleGraph, runtime, runtimeRequirements }
	) {
		const dep = /** @type {CommonJsSelfReferenceDependency} */ (dependency);
		let used;
		if (dep.names.length === 0) {
			used = dep.names;
		} else {
			used = moduleGraph.getExportsInfo(module).getUsedName(dep.names, runtime);
		}
		if (!used) {
			throw new Error(
				"Self-reference dependency has unused export name: This should not happen"
			);
		}

		let base = undefined;
		switch (dep.base) {
			case "exports":
				runtimeRequirements.add(RuntimeGlobals.exports);
				base = module.exportsArgument;
				break;
			case "module.exports":
				runtimeRequirements.add(RuntimeGlobals.module);
				base = `${module.moduleArgument}.exports`;
				break;
			case "this":
				runtimeRequirements.add(RuntimeGlobals.thisAsExports);
				base = "this";
				break;
			default:
				throw new Error(`Unsupported base ${dep.base}`);
		}

		if (base === dep.base && equals(used, dep.names)) {
			// Nothing has to be changed
			// We don't use a replacement for compat reasons
			// for plugins that update `module._source` which they
			// shouldn't do!
			return;
		}

		source.replace(
			dep.range[0],
			dep.range[1] - 1,
			`${base}${propertyAccess(used)}`
		);
	}
};

module.exports = CommonJsSelfReferenceDependency;