94 lines
3.1 KiB
JavaScript
94 lines
3.1 KiB
JavaScript
/*
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Copyright (c) 2014 Google Inc. All rights reserved.
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Copyright (c) 2012-2013 Johannes Ewald.
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Use of this source code is governed by the MIT License, available in this package's LICENSE file
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or at http://opensource.org/licenses/MIT.
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*/
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/** @module lib/requizzle */
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const loader = require('./loader');
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const Module = require('module');
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/**
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* Function that returns text to swizzle into the module.
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*
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* @typedef module:lib/requizzle~wrapperFunction
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* @type {function}
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* @param {string} targetPath - The path to the target module.
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* @param {string} parentModulePath - The path to the module that is requiring the target module.
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* @return {string} The text to insert before or after the module's source code.
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*/
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/**
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* Options for the wrappers that will be swizzled into the target module.
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*
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* @typedef module:lib/requizzle~options
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* @type {Object}
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* @property {Object=} options.extras - Functions that generate text to swizzle into the target
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* module.
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* @property {module:lib/requizzle~wrapperFunction} options.extras.after - Function that returns
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* text to insert after the module's source code.
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* @property {module:lib/requizzle~wrapperFunction} options.extras.before - Function that returns
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* text to insert before the module's source code.
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* @property {(Array.<string>|string)} options.requirePaths - Additional paths to search when
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* resolving module paths in the target module.
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*/
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function isNativeModule(targetPath, parentModule) {
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const lookupPaths = Module._resolveLookupPaths(targetPath, parentModule, true);
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/* istanbul ignore next */
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return lookupPaths === null ||
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(lookupPaths.length === 2 &&
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lookupPaths[1].length === 0 &&
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lookupPaths[0] === targetPath);
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}
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/**
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* Create a `Requizzle` instance. If you provide options, Requizzle will default to those options
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* when you call {@link Requizzle#requizzle}.
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*
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* @class
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* @param {!module:lib/requizzle~options} options - Options for the wrappers that will be swizzled
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* into the target module.
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* @param {Object=} cache - For internal use.
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*/
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class Requizzle {
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constructor(options, cache) {
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this._options = options;
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this._cache = cache || {
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module: {},
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source: {}
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};
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}
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/**
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* Load the module, swizzling in the requested changes.
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*
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* @param {!string} targetPath - The path to the module that will be loaded.
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* @return {Module} The swizzled module.
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*/
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requizzle(targetPath) {
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const options = this._options;
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const parentModule = options.parent;
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let targetModule;
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let wrapper;
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// Don't interfere with native modules
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if (isNativeModule(targetPath, parentModule)) {
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return require(targetPath);
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}
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// Resolve the filename relative to the parent module
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targetPath = Module._resolveFilename(targetPath, parentModule);
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wrapper = loader.createWrapper(targetPath, parentModule, this._cache, this._options);
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targetModule = loader.load(targetPath, parentModule, wrapper, this._cache, this._options);
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return targetModule.exports;
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}
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}
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module.exports = Requizzle;
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