/**

* @license

* Copyright Google LLC All Rights Reserved.

*

* Use of this source code is governed by an MIT-style license that can be

* found in the LICENSE file at https://angular.dev/license

*/

/**

* @fileoverview

*

* Module loader that augments NodeJS's execution to:

*

* - support native execution of Angular JavaScript output

* that isn't strict ESM at this point (lack of explicit extensions).

* - support path mappings at runtime. This allows us to natively execute ESM

* without having to pre-bundle for testing, or use the slow full npm linked packages

*/

import {parseTsconfig, createPathsMatcher} from 'get-tsconfig';

import path from 'node:path';

const explicitExtensionRe = /\.[mc]?js$/;

const nonModuleImportRe = /^[.\/]/;

const runfilesRoot = process.env.JS_BINARY__RUNFILES;

const tsconfigPath = path.join(runfilesRoot, '_main/packages/tsconfig-build.json');

const tsconfig = parseTsconfig(tsconfigPath);

const pathMappingMatcher = createPathsMatcher({config: tsconfig, path: tsconfigPath});

/** @type {import('module').ResolveHook} */

export const resolve = async (specifier, context, nextResolve) => {

// True when it's a non-module import without explicit extensions.

const isNonModuleExtensionlessImport =

nonModuleImportRe.test(specifier) && !explicitExtensionRe.test(specifier);

const pathMappings = !nonModuleImportRe.test(specifier) ? pathMappingMatcher(specifier) : [];

// If it's neither path mapped, nor an extension-less import that may be fixed up, exit early.

if (!isNonModuleExtensionlessImport && pathMappings.length === 0) {

return nextResolve(specifier, context);

}

if (pathMappings.length > 0) {

for (const mapping of pathMappings) {

const res = await catchError(() => resolve(mapping, context, nextResolve));

if (res !== null) {

return res;

}

}

} else {

const fixedResult =

(await catchError(() => nextResolve(`${specifier}.js`, context))) ||

(await catchError(() => nextResolve(`${specifier}/index.js`, context))) ||

// Legacy variants for the `zone.js` variant using still `ts_library`.

// TODO(rules_js migration): Remove this.

(await catchError(() => nextResolve(`${specifier}.mjs`, context))) ||

(await catchError(() => nextResolve(`${specifier}/index.mjs`, context)));

if (fixedResult !== null) {

return fixedResult;

}

}

return await nextResolve(specifier, context);

};

async function catchError(fn) {

try {

return await fn();

} catch {

return null;

}

}