module-importer.cjs•2.57 kB
/**
* @fileoverview Universal module importer
*/
//-----------------------------------------------------------------------------
// Imports
//-----------------------------------------------------------------------------
const { createRequire } = require("module");
const { pathToFileURL } = require("url");
//-----------------------------------------------------------------------------
// Helpers
//-----------------------------------------------------------------------------
const SLASHES = new Set(["/", "\\"]);
/**
* Normalizes directories to have a trailing slash.
* Resolve is pretty finicky -- if the directory name doesn't have
* a trailing slash then it tries to look in the parent directory.
* i.e., if the directory is "/usr/nzakas/foo" it will start the
* search in /usr/nzakas. However, if the directory is "/user/nzakas/foo/",
* then it will start the search in /user/nzakas/foo.
* @param {string} directory The directory to check.
* @returns {string} The normalized directory.
*/
function normalizeDirectory(directory) {
if (!SLASHES.has(directory[directory.length-1])) {
return directory + "/";
}
return directory;
}
//-----------------------------------------------------------------------------
// Exports
//-----------------------------------------------------------------------------
/**
* Class for importing both CommonJS and ESM modules in Node.js.
*/
exports.ModuleImporter = class ModuleImporter {
/**
* Creates a new instance.
* @param {string} [cwd] The current working directory to resolve from.
*/
constructor(cwd = process.cwd()) {
/**
* The base directory from which paths should be resolved.
* @type {string}
*/
this.cwd = normalizeDirectory(cwd);
}
/**
* Resolves a module based on its name or location.
* @param {string} specifier Either an npm package name or
* relative file path.
* @returns {string|undefined} The location of the import.
* @throws {Error} If specifier cannot be located.
*/
resolve(specifier) {
const require = createRequire(this.cwd);
return require.resolve(specifier);
}
/**
* Imports a module based on its name or location.
* @param {string} specifier Either an npm package name or
* relative file path.
* @returns {Promise<object>} The module's object.
*/
import(specifier) {
const location = this.resolve(specifier);
return import(pathToFileURL(location).href);
}
}