node_modules/enhanced-resolve/lib/DescriptionFilePlugin.js

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

const DescriptionFileUtils = require("./DescriptionFileUtils");

module.exports = class DescriptionFilePlugin {
	constructor(source, filenames, target) {
		this.source = source;
		this.filenames = [].concat(filenames);
		this.target = target;
	}

	apply(resolver) {
		const target = resolver.ensureHook(this.target);
		resolver
			.getHook(this.source)
			.tapAsync(
				"DescriptionFilePlugin",
				(request, resolveContext, callback) => {
					const directory = request.path;
					DescriptionFileUtils.loadDescriptionFile(
						resolver,
						directory,
						this.filenames,
						resolveContext,
						(err, result) => {
							if (err) return callback(err);
							if (!result) {
								if (resolveContext.missing) {
									this.filenames.forEach(filename => {
										resolveContext.missing.add(
											resolver.join(directory, filename)
										);
									});
								}
								if (resolveContext.log)
									resolveContext.log("No description file found");
								return callback();
							}
							const relativePath =
								"." +
								request.path
									.substr(result.directory.length)
									.replace(/\\/g, "/");
							const obj = Object.assign({}, request, {
								descriptionFilePath: result.path,
								descriptionFileData: result.content,
								descriptionFileRoot: result.directory,
								relativePath: relativePath
							});
							resolver.doResolve(
								target,
								obj,
								"using description file: " +
									result.path +
									" (relative path: " +
									relativePath +
									")",
								resolveContext,
								(err, result) => {
									if (err) return callback(err);

									// Don't allow other processing
									if (result === undefined) return callback(null, null);
									callback(null, result);
								}
							);
						}
					);
				}
			);
	}
};