node-internal-modules-cjs-helpers.js•2.74 kB
// Copied from https://github.com/nodejs/node/blob/v17.0.1/lib/internal/modules/cjs/helpers.js
'use strict';
const {
ArrayPrototypeForEach,
ObjectDefineProperty,
ObjectPrototypeHasOwnProperty,
SafeSet,
StringPrototypeIncludes,
StringPrototypeStartsWith,
} = require('./node-primordials');
const { getOptionValue } = require('./node-options');
const userConditions = getOptionValue('--conditions');
const noAddons = getOptionValue('--no-addons');
const addonConditions = noAddons ? [] : ['node-addons'];
// TODO: Use this set when resolving pkg#exports conditions in loader.js.
const cjsConditions = new SafeSet([
'require',
'node',
...addonConditions,
...userConditions,
]);
/**
* @param {any} object
* @param {string} [dummyModuleName]
* @return {void}
*/
function addBuiltinLibsToObject(object, dummyModuleName) {
// Make built-in modules available directly (loaded lazily).
const Module = require('module').Module;
const { builtinModules } = Module;
// To require built-in modules in user-land and ignore modules whose
// `canBeRequiredByUsers` is false. So we create a dummy module object and not
// use `require()` directly.
const dummyModule = new Module(dummyModuleName);
ArrayPrototypeForEach(builtinModules, (name) => {
// Neither add underscored modules, nor ones that contain slashes (e.g.,
// 'fs/promises') or ones that are already defined.
if (StringPrototypeStartsWith(name, '_') ||
StringPrototypeIncludes(name, '/') ||
ObjectPrototypeHasOwnProperty(object, name)) {
return;
}
// Goals of this mechanism are:
// - Lazy loading of built-in modules
// - Having all built-in modules available as non-enumerable properties
// - Allowing the user to re-assign these variables as if there were no
// pre-existing globals with the same name.
const setReal = (val) => {
// Deleting the property before re-assigning it disables the
// getter/setter mechanism.
delete object[name];
object[name] = val;
};
ObjectDefineProperty(object, name, {
get: () => {
// Node 12 hack; remove when we drop node12 support
const lib = (dummyModule.require || require)(name);
// Disable the current getter/setter and set up a new
// non-enumerable property.
delete object[name];
ObjectDefineProperty(object, name, {
get: () => lib,
set: setReal,
configurable: true,
enumerable: false
});
return lib;
},
set: setReal,
configurable: true,
enumerable: false
});
});
}
exports.addBuiltinLibsToObject = addBuiltinLibsToObject;
exports.cjsConditions = cjsConditions;