webpack/lib/dependencies/CommonJsSelfReferenceDependency.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 Tobias Koppers @sokra
*/

"use strict";

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

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").ReferencedExports} ReferencedExports */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../ExportsInfo").ExportInfoName} ExportInfoName */
/** @typedef {import("../javascript/JavascriptParser").Range} Range */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
/** @typedef {import("../util/runtime").RuntimeSpec} RuntimeSpec */
/** @typedef {import("./CommonJsDependencyHelpers").CommonJSDependencyBaseKeywords} CommonJSDependencyBaseKeywords */

class CommonJsSelfReferenceDependency extends NullDependency {
	/**
	 * Creates an instance of CommonJsSelfReferenceDependency.
	 * @param {Range} range range
	 * @param {CommonJSDependencyBaseKeywords} base base
	 * @param {ExportInfoName[]} names names
	 * @param {boolean} call is a call
	 */
	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 an identifier to merge equal requests.
	 * @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 {ReferencedExports} referenced exports
	 */
	getReferencedExports(moduleGraph, runtime) {
		return [this.call ? this.names.slice(0, -1) : this.names];
	}

	/**
	 * Serializes this instance into the provided serializer context.
	 * @param {ObjectSerializerContext} context context
	 */
	serialize(context) {
		const { write } = context;
		write(this.range);
		write(this.base);
		write(this.names);
		write(this.call);
		super.serialize(context);
	}

	/**
	 * Restores this instance from the provided deserializer context.
	 * @param {ObjectDeserializerContext} context 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
) {
	/**
	 * Applies the plugin by registering its hooks on the compiler.
	 * @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);
		const used =
			dep.names.length === 0
				? dep.names
				: moduleGraph.getExportsInfo(module).getUsedName(dep.names, runtime);
		if (!used) {
			throw new Error(
				"Self-reference dependency has unused export name: This should not happen"
			);
		}

		/** @type {string} */
		let base;
		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;