webpack/lib/Dependency.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const DependencyReference = require("./dependencies/DependencyReference");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("./ChunkGraph")} ChunkGraph */
/** @typedef {import("./DependencyTemplates")} DependencyTemplates */
/** @typedef {import("./Module")} Module */
/** @typedef {import("./ModuleGraph")} ModuleGraph */
/** @typedef {import("./RuntimeTemplate")} RuntimeTemplate */
/** @typedef {import("./WebpackError")} WebpackError */
/** @typedef {import("./util/createHash").Hash} Hash */

/** @typedef {Object} SourcePosition
 *  @property {number} line
 *  @property {number=} column
 */

/** @typedef {Object} RealDependencyLocation
 *  @property {SourcePosition} start
 *  @property {SourcePosition=} end
 *  @property {number=} index
 */

/** @typedef {Object} SynteticDependencyLocation
 *  @property {string} name
 *  @property {number=} index
 */

/** @typedef {SynteticDependencyLocation|RealDependencyLocation} DependencyLocation */

/**
 * @typedef {Object} ExportSpec
 * @property {string} name the name of the export
 * @property {Module=} from  when reexported: from which module
 * @property {string[] | null=} export  when reexported: from which export
 */

/**
 * @typedef {Object} ExportsSpec
 * @property {(string | ExportSpec)[] | true | null} exports exported names, true for unknown exports or null for no exports
 * @property {Module[]=} dependencies module on which the result depends on
 */

class Dependency {
	constructor() {
		// TODO remove in webpack 5
		/** @type {boolean} */
		this.weak = false;
		/** @type {boolean} */
		this.optional = false;
		/** @type {DependencyLocation} */
		this.loc = undefined;
	}

	/**
	 * @returns {string} a display name for the type of dependency
	 */
	get type() {
		return "unknown";
	}

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

	// TODO check if this can be moved into ModuleDependency
	/**
	 * Returns the referenced module and export
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {DependencyReference} reference
	 */
	getReference(moduleGraph) {
		const module = moduleGraph.getModule(this);
		if (!module) return null;
		return new DependencyReference(
			() => moduleGraph.getModule(this),
			DependencyReference.NS_OBJECT_IMPORTED,
			this.weak
		);
	}

	/**
	 * Returns the exported names
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {ExportsSpec | undefined} export names
	 */
	getExports(moduleGraph) {
		return undefined;
	}

	/**
	 * Returns warnings
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {WebpackError[]} warnings
	 */
	getWarnings(moduleGraph) {
		return null;
	}

	/**
	 * Returns errors
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {WebpackError[]} errors
	 */
	getErrors(moduleGraph) {
		return null;
	}

	/**
	 * Update the hash
	 * @param {Hash} hash hash to be updated
	 * @param {ChunkGraph} chunkGraph chunk graph
	 * @returns {void}
	 */
	updateHash(hash, chunkGraph) {
		const module = chunkGraph.moduleGraph.getModule(this);
		if (module) {
			hash.update(chunkGraph.getModuleId(module) + "");
		}
	}

	/**
	 * implement this method to allow the occurrence order plugin to count correctly
	 * @returns {number} count how often the id is used in this dependency
	 */
	getNumberOfIdOccurrences() {
		return 1;
	}

	serialize({ write }) {
		write(this.weak);
		write(this.optional);
		write(this.loc);
	}

	deserialize({ read }) {
		this.weak = read();
		this.optional = read();
		this.loc = read();
	}
}

Object.defineProperty(Dependency.prototype, "module", {
	/**
	 * @deprecated
	 * @returns {never} throws
	 */
	get() {
		throw new Error(
			"module property was removed from Dependency (use compilation.moduleGraph.getModule(dependency) instead)"
		);
	},

	/**
	 * @deprecated
	 * @returns {never} throws
	 */
	set() {
		throw new Error(
			"module property was removed from Dependency (use compilation.moduleGraph.updateModule(dependency, module) instead)"
		);
	}
});

Object.defineProperty(Dependency.prototype, "disconnect", {
	get() {
		throw new Error(
			"disconnect was removed from Dependency (Dependency no longer carries graph specific information)"
		);
	}
});

module.exports = Dependency;