rollup-plugin-shim

1.0.0 verified Mon Apr 27 auth: no javascript maintenance

A Rollup plugin that replaces module imports with a specified string shim, useful for stripping out dev-time dependencies like 'debug' in production builds. Stable at v1.0.0 since 2017, with minimal releases. Unlike rollup-plugin-alias, this plugin replaces the module content inline with a string rather than pointing to another file, making it ideal for small shims. Best for simple noop replacements; for complex aliasing, use rollup-plugin-alias instead. Active maintenance is low, but the plugin works with Rollup 0.x and 1.x.

Common errors

error Error: Unexpected token (Note that you need plugins to import files that are not JavaScript) ↓

cause Shim string contains syntax errors or invalid module format.

fix

Correct the shim string to be valid ES module syntax.

error TypeError: shim is not a function ↓

cause Importing the plugin incorrectly (e.g., using named import when default is needed).

fix

Use default import: import shim from 'rollup-plugin-shim'.

error Error: Cannot find module 'rollup-plugin-shim' ↓

cause Package not installed or not in node_modules.

fix

Run npm install rollup-plugin-shim --save-dev or yarn add -D rollup-plugin-shim.

Warnings

gotcha Plugin overwrites imports globally; if two modules use the same import name but expect different behavior, shimming may break one of them. ↓

fix Use distinct keys or handle per-module with custom resolve.

gotcha Shim values are strings that are evaluated as modules; syntax errors in the shim string will cause build failures. ↓

fix Ensure shim strings are valid JavaScript/ES module syntax.

gotcha The plugin may not work with Rollup >=2.0.0 due to API changes; it was developed for Rollup 0.x/1.x. ↓

fix Test with your Rollup version; consider using '@rollup/plugin-alias' or newer alternatives.

gotcha Keys in the shim object must match the import specifier exactly, including file extensions if used in the import. ↓

fix Use full paths or bare specifiers as they appear in import statements.

Install

npm install rollup-plugin-shim

yarn add rollup-plugin-shim

pnpm add rollup-plugin-shim

Imports

default (shim)
wrong
```
import { shim } from 'rollup-plugin-shim'
```
correct
```
import shim from 'rollup-plugin-shim'
```
The package exports a single default function; named import will result in undefined.
shim (CommonJS)
```
const shim = require('rollup-plugin-shim')
```
CommonJS require works, but Rollup configs typically use ESM import.

shim (TypeScript)

wrong

import shim from 'rollup-plugin-shim'  // not typed, use require for TS compatibility

correct

import shim = require('rollup-plugin-shim')

Package has no TypeScript definitions; use require style or add a module declaration.

Quickstart

Shows how to configure the plugin to replace 'debug' and 'fs' imports with noop stubs in a Rollup config.

import shim from 'rollup-plugin-shim';

export default {
  input: 'src/main.js',
  output: { format: 'es' },
  plugins: [
    shim({
      'debug': `export default () => () => undefined`,
      'fs': `export function writeFileSync() {}`
    })
  ]
};