Registry / devops / babel-plugin-define-var

babel-plugin-define-var

library0.1.0jsnpmunverified

A Babel plugin (v0.1.0) that adds missing variable declarations in the root scope after wyw-in-js pre-evaluation removes some identifiers, fixing '_c is not defined' errors. Useful for projects using MUI system, emotion, or styled-components with React Refresh (Next.js, Vite). The plugin is minimal and specific—there are no alternatives with the same narrow fix. Release cadence is low; this is the only version. No breaking changes expected due to simple scope.

devops

npm install babel-plugin-define-var

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-DEFIN

babel-plugin-define-var

devopsjavascriptv0.1.0

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.

default

✓ import plugin from 'babel-plugin-define-var'

✗ const plugin = require('babel-plugin-define-var')

ESM only; no named export.

plugin

✓ // .babelrc { "plugins": ["babel-plugin-define-var"] }

Configure via string in Babel config, not imported directly.

plugin

✓ const plugin = require('babel-plugin-define-var').default

✗ const plugin = require('babel-plugin-define-var')

In CommonJS, must use .default because plugin is a default export.

Configures Babel plugin to fix missing variable declarations after wyw-in-js pre-evaluation with React Refresh.

// Install first: npm install babel-plugin-define-var // .babelrc { "plugins": ["babel-plugin-define-var"] } // Or in babel.config.js: module.exports = { plugins: ['babel-plugin-define-var'], }; // The plugin will automatically add missing var declarations like '_c = ...'

Debug

Known issues

gotchaPlugin only targets root scope; if missing declarations are nested, it won't fix them.

fix

Check plugin source or file an issue if nested vars are missing.

affects: >=0.1.0

gotchaOnly works when wyw-in-js is used; plugin does nothing otherwise.

fix

Ensure wyw-in-js is in your Babel chain and produces the missing var problem.

affects: >=0.1.0

Errors

Common errors & fixes

_c is not defined

wyw-in-js pre-evaluation removes variable declaration for '_c' when paired with React Refresh.

fix

Add babel-plugin-define-var to your Babel plugins.

_c1 is not defined

Same as above but for second variable.

fix

Add babel-plugin-define-var to your Babel plugins.

$RefreshReg$ is not defined

React Refresh global not available during wyw-in-js evaluation; plugin does not fix this.

fix

Ensure React Refresh is properly set up (e.g., in Next.js or Vite) and wyw-in-js config removes it.

Upgrade

Version history

0.1.0latest on npm

Audit

Dependencies

@babel/corerequiredBabel plugin API dependency, used at runtime

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/siriwatknp/babel-plugin-define-var ↗

packagehttps://www.npmjs.com/package/babel-plugin-define-var ↗