bootstrap-node.js

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

//@ts-check
'use strict';

/**
 * Add support for redirecting the loading of node modules
 *
 * @param {string} injectPath
 */
exports.injectNodeModuleLookupPath = function (injectPath) {
	if (!injectPath) {
		throw new Error('Missing injectPath');
	}

	const Module = require('module');
	const path = require('path');

	const nodeModulesPath = path.join(__dirname, '../node_modules');

	// @ts-ignore
	const originalResolveLookupPaths = Module._resolveLookupPaths;

	// @ts-ignore
	Module._resolveLookupPaths = function (moduleName, parent) {
		const paths = originalResolveLookupPaths(moduleName, parent);
		if (Array.isArray(paths)) {
			for (let i = 0, len = paths.length; i < len; i++) {
				if (paths[i] === nodeModulesPath) {
					paths.splice(i, 0, injectPath);
					break;
				}
			}
		}

		return paths;
	};
};

exports.removeGlobalNodeModuleLookupPaths = function () {
	const Module = require('module');
	// @ts-ignore
	const globalPaths = Module.globalPaths;

	// @ts-ignore
	const originalResolveLookupPaths = Module._resolveLookupPaths;

	// @ts-ignore
	Module._resolveLookupPaths = function (moduleName, parent) {
		const paths = originalResolveLookupPaths(moduleName, parent);
		let commonSuffixLength = 0;
		while (commonSuffixLength < paths.length && paths[paths.length - 1 - commonSuffixLength] === globalPaths[globalPaths.length - 1 - commonSuffixLength]) {
			commonSuffixLength++;
		}
		return paths.slice(0, paths.length - commonSuffixLength);
	};
};