Registry / testing / babel-plugin-rewire-ts

babel-plugin-rewire-ts

library1.4.0jsnpmunverified

A Babel plugin that enables mocking of module dependencies for testing, based on the rewire.js concept. The current stable version is 1.4.0, with a release cadence that is maintenance-focused. It is a fork of babel-plugin-rewire with added TypeScript compatibility. Key differentiators: it works with TypeScript, supports ES6 imports, CommonJS require(), and named/top-level function rewiring. It provides a RewireAPI object for convenient mocking in tests. It is specifically designed for unit testing where module dependencies need to be replaced with mocks or stubs.

testing

npm install babel-plugin-rewire-ts

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-REWIR

babel-plugin-rewire-ts

testingjavascriptv1.4.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

__Rewire__

✓ import { __Rewire__ } from 'babel-plugin-rewire-ts'

✗ const __Rewire__ = require('babel-plugin-rewire-ts').__Rewire__

This is a babel plugin, not a runtime import. The rewire methods are injected into your modules at build time.

__get__

✓ import ModuleUnderTest from './module'; ModuleUnderTest.__get__('dependency')

Not directly imported from the plugin; it's exported from the transformed module.

__ResetDependency__

✓ import { __ResetDependency__ } from 'babel-plugin-rewire-ts'

Same as above; not a runtime import.

Demonstrates basic setup and usage of babel-plugin-rewire-ts to mock a module dependency in tests.

// Install: npm install babel-plugin-rewire-ts --save-dev // .babelrc or babel.config.js { "plugins": [ ["babel-plugin-rewire-ts", {}] ] } // module.js import { getData } from './api'; export function fetchAndProcess() { return getData().then(data => data.map(x => x * 2)); } // test.js import { fetchAndProcess } from './module'; const apiMock = { getData: () => Promise.resolve([1, 2, 3]) }; fetchAndProcess.__Rewire__('getData', apiMock.getData); fetchAndProcess().__then(result => { console.log(result); // [2, 4, 6] fetchAndProcess.__ResetDependency__('getData'); });

Debug

Known issues

gotchaRewired dependencies do not affect other modules that import the same dependency; each module's rewiring is isolated.

fix

Ensure that you reset dependencies after each test to avoid cross-test contamination.

affects: *

deprecatedAs of v1.4.0, __Rewire__ and __ResetDependency__ should be used instead of __set__ and __get__ for external state reflection.

fix

Update test code to use __Rewire__ and __ResetDependency__ for consistency and proper external state handling.

affects: >=1.4.0

breakingv1.4.0 syncs internal and external state, which may break tests that relied on the old behavior where rewiring only affected internal state.

fix

Review tests that use __get__ to fetch internal state; after v1.4.0, the external state should reflect rewires, so __get__ might not be necessary.

affects: >=1.4.0

gotchaCommonJS require() rewiring works only for top-level var declarations, not arbitrary require calls inside functions.

fix

Ensure that require() calls to be rewired are assigned to top-level variables in the module.

affects: *

Errors

Common errors & fixes

SyntaxError: Unexpected token (5:10) when using TypeScript with babel-plugin-rewire-ts

The plugin may not handle TypeScript syntax properly without appropriate Babel presets.

fix

Ensure you have @babel/preset-typescript installed and configured in your Babel config.

Cannot find module 'babel-plugin-rewire-ts' from '...'

The plugin is not installed or is not in the correct location.

fix

Run npm install babel-plugin-rewire-ts --save-dev and check that it's listed in your Babel plugins.

TypeError: ...__Rewire__ is not a function

The module was not transformed by the Babel plugin, likely because the plugin is not configured correctly.

fix

Verify that babel-plugin-rewire-ts is included in your Babel config and that your test files are included in the Babel transformation.

Upgrade

Version history

1.4.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

16 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/rosswarren/babel-plugin-rewire-ts ↗

packagehttps://www.npmjs.com/package/babel-plugin-rewire-ts ↗