Disable __dirname & __filename webpack polyfills by dangrima90 · Pull Request #11146 · NativeScript/NativeScript

dangrima90 · 2026-03-27T17:45:03Z

PR Checklist

The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/CONTRIBUTING.md#commit-messages.
There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
You have signed the CLA.
All existing tests are passing: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/DevelopmentWorkflow.md#running-unit-tests-application.
Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/tools/notes/WritingUnitTests.md.

What is the current behavior?

As discussed here: https://discord.com/channels/603595811204366337/1481617562310676620/1487134181602361444, when importing ESM libraries in workers is causing an error on iOS.

For example:

Error instantiating module: [redacted_path]/src_workers_csv-generation-worker_js.mjs
  Native stack trace:
    [redacted_stack]
  JavaScript error:
  SyntaxError: The requested module 'node:url' does not provide an export named 'fileURLToPath'
  Module instantiation failed: [redacted_path]/src_workers_csv-generation-worker_js.mjs
  Debug mode - ES module returned empty namespace, but telling iOS it succeeded

To help explain the issue via claude code it described the issue with the following:

The failure chain is:

Your code: Worker imports getNumberLocale from @my-scope/helpers (now ESM)

helpers ESM causes webpack to output the worker as an ESM bundle (.mjs) instead of CJS

NativeScript itself — specifically @nativescript/core/globals/index.js:15:

global.__dirname = typeof __dirname !== 'undefined' ? __dirname : import.meta.dirname;

This references __dirname, which webpack detects in ESM output mode and auto-generates:

import {fileURLToPath} from "node:url"; // ← webpack's own generated code

iOS doesn't expose fileURLToPath from node:url → crash

What is the new behavior?

The fix applied with this PR disables webpack's polyfills for __dirname and __filename as NativeScript already handles these.

nx-cloud · 2026-03-27T18:28:43Z

View your CI Pipeline Execution ↗ for commit 025eb51

Command	Status	Duration	Result
`nx test apps-automated -c=android`	✅ Succeeded	3m 22s	View ↗
`nx run-many --target=test --configuration=ci --...`	✅ Succeeded	3s	View ↗

☁️ Nx Cloud last updated this comment at 2026-03-27 18:34:04 UTC

Copilot

Pull request overview

This PR updates NativeScript’s webpack5 base configuration to avoid webpack’s automatic __dirname/__filename polyfills in ESM output, preventing an iOS worker crash caused by webpack generating import { fileURLToPath } from "node:url".

Changes:

Disable webpack’s __dirname and __filename handling in the ESM output branch via config.node.set('__dirname', false) / config.node.set('__filename', false).
Add explanatory inline comments describing the iOS worker failure mode and why the webpack behavior is undesirable in this environment.

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Copilot · 2026-03-27T19:12:02Z

packages/webpack5/src/configuration/base.ts

+		// NativeScript's runtime already provides __dirname as a global, and
+		// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
+		// so webpack's polyfill is both redundant and broken on iOS.


The new inline comment says "NativeScript's runtime already provides __dirname as a global", but in @nativescript/core/globals/index.ts the code explicitly notes that __dirname is not defined in ESM builds and instead populates global.__dirname from import.meta.dirname. To avoid misleading future maintainers, update this comment to refer to global.__dirname (and/or import.meta.dirname) rather than implying the __dirname identifier exists in ESM.

Suggested change

// NativeScript's runtime already provides __dirname as a global, and

// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,

// so webpack's polyfill is both redundant and broken on iOS.

// NativeScript's runtime already provides a __dirname value via global.__dirname, and

// @nativescript/core/globals/index.js handles the ESM case by deriving global.__dirname

// from import.meta.dirname, so webpack's polyfill is both redundant and broken on iOS.

Copilot · 2026-03-27T19:12:02Z

packages/webpack5/src/configuration/base.ts

+		// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.
+		// In ESM output mode, webpack auto-generates this import whenever bundled code references
+		// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.
+		// NativeScript's runtime already provides __dirname as a global, and
+		// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
+		// so webpack's polyfill is both redundant and broken on iOS.
+		config.node.set('__dirname', false);
+		config.node.set('__filename', false);


This change affects the ESM output path only, but the existing packages/webpack5/__tests__/configuration/base.spec.ts snapshot coverage appears to exercise only the CommonJS configuration (no experiments.outputModule / output.module assertions). Add a unit test that forces the ESM branch (e.g., by mocking the runtime dependency version check to >=9) and asserts node.__dirname/node.__filename are disabled, so regressions in worker ESM bundling are caught.

Suggested change

// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.

// In ESM output mode, webpack auto-generates this import whenever bundled code references

// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.

// NativeScript's runtime already provides __dirname as a global, and

// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,

// so webpack's polyfill is both redundant and broken on iOS.

config.node.set('__dirname', false);

config.node.set('__filename', false);

// Determine NativeScript runtime version (iOS/Android) so we only disable

// webpack's __dirname/__filename polyfills on runtimes that support the

// ESM helpers used by @nativescript/core (e.g., import.meta.dirname).

const nsRuntimeVersionForCheck =

getResolvedDependencyVersionForCheck('@nativescript/ios') ??

getResolvedDependencyVersionForCheck('@nativescript/android');

if (nsRuntimeVersionForCheck && isVersionGteConsideringPrerelease(nsRuntimeVersionForCheck, '9.0.0')) {

// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.

// In ESM output mode, webpack auto-generates this import whenever bundled code references

// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.

// NativeScript's runtime already provides __dirname as a global, and

// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,

// so webpack's polyfill is both redundant and broken on iOS for supported runtimes.

config.node.set('__dirname', false);

config.node.set('__filename', false);

}

Ignore __dirname & __filename webpack polyfills

025eb51

dangrima90 changed the title ~~Ignore __dirname & __filename webpack polyfills~~ Disable __dirname & __filename webpack polyfills Mar 27, 2026

NathanWalker requested a review from Copilot March 27, 2026 19:07

NathanWalker added ♥ community PR review-in-progress labels Mar 27, 2026

NathanWalker self-assigned this Mar 27, 2026

Copilot started reviewing on behalf of NathanWalker March 27, 2026 19:08 View session

Copilot AI reviewed Mar 27, 2026

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Disable dirname & filename webpack polyfills#11146

Disable dirname & filename webpack polyfills#11146
dangrima90 wants to merge 1 commit intoNativeScript:mainfrom
dangrima90:fix/ignore-dirname-filename-webpack-polyfills

dangrima90 commented Mar 27, 2026 •

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dangrima90 commented Mar 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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PR Checklist

What is the current behavior?

What is the new behavior?

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dangrima90 commented Mar 27, 2026 •

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