rollup-plugin-banner

0.2.1 verified Mon Apr 27 auth: no javascript

Rollup plugin that appends content before the JS bundle file, preserving the banner even after minification with plugins like rollup-plugin-uglify, which Rollup's built-in output.banner does not. Version 0.2.1 is the latest stable release. Differentiates from output.banner by ensuring the banner survives all plugin transformations.

Common errors

error Error: [object Object] is not a valid banner option ↓

cause Passing an object with unknown properties (e.g., missing 'file' key).

fix

Use an object with 'file' and optional 'encoding' keys.

error Cannot find module 'rollup-plugin-banner' ↓

cause Plugin not installed as devDependency.

fix

Run: npm install --save-dev rollup-plugin-banner

error SyntaxError: Unexpected token '<' ↓

cause Using 'import' syntax in a CommonJS context without transpilation.

fix

Use const banner = require('rollup-plugin-banner') instead of import.

Warnings

gotcha Banner is appended before the bundle content, not comments – ensure your banner string does not break JavaScript syntax. ↓

fix Wrap banner in comment syntax if needed, e.g., '/* My Banner */'

deprecated No new releases since 2020; plugin may be unmaintained. ↓

fix Consider using Rollup's built-in output.banner if not using minification plugins that strip it, or switch to active alternatives.

gotcha The banner is added as a string literal – template interpolation uses <%= %> syntax, not backticks. ↓

fix Use banner('String <%= pkg.xxx %>') instead of banner(`String ${pkg.xxx}`)

Install

npm install rollup-plugin-banner

yarn add rollup-plugin-banner

pnpm add rollup-plugin-banner

Imports

banner
wrong
```
const banner = require('rollup-plugin-banner')
```
correct
```
import banner from 'rollup-plugin-banner'
```
Default ESM export – CommonJS require works but is less common in Rollup configs.

banner

wrong

import { banner } from 'rollup-plugin-banner'

correct

const banner = require('rollup-plugin-banner')

The module is a default export, not a named export.

banner

wrong

import * as banner from 'rollup-plugin-banner'

correct

import banner from 'rollup-plugin-banner'

Namespace import is unnecessary and may cause issues.

Quickstart

Demonstrates adding a banner to a Rollup bundle using the default export and template strings from package.json.

import banner from 'rollup-plugin-banner';

export default {
  input: 'src/main.js',
  output: {
    file: 'dist/bundle.js',
    format: 'iife',
  },
  plugins: [
    banner('MyApp v<%= pkg.version %> by <%= pkg.author %>')
  ]
};