rollup-plugin-preprocess

0.0.4 verified Mon Apr 27 auth: no javascript deprecated

A Rollup plugin that integrates the Preprocess library to conditionally include or exclude parts of files (HTML, JS, etc.) based on a user-defined context (e.g., DEBUG flags). The latest stable version is 0.0.4 (released November 2016). Development appears to be stalled with no recent releases or maintenance; this plugin is a thin wrapper around the `preprocess` package for Rollup build pipelines. Alternatives include `@rollup/plugin-replace` or direct use of `preprocess` with other Rollup hooks. The plugin supports simple context-based preprocessing but lacks extensive documentation and has limited adoption.

Common errors

error Error: Cannot find module 'rollup-pluginutils' ↓

cause Missing dependency rollup-pluginutils which is a peer dependency.

fix

npm install rollup-pluginutils --save-dev

error TypeError: preprocess is not a function ↓

cause Using named import when only default export exists.

fix

Use import preprocess from 'rollup-plugin-preprocess' instead of import { preprocess } from 'rollup-plugin-preprocess'

Warnings

deprecated This package has not been updated since 2016 and is essentially unmaintained. Consider using modern alternatives like @rollup/plugin-replace. ↓

fix Migrate to @rollup/plugin-replace or use the preprocess library directly with a custom Rollup plugin.

gotcha The plugin does not handle TypeScript or Vue files out-of-the-box; you may need to adjust the include/exclude filter. ↓

fix Manually specify the include and exclude options in the plugin configuration.

gotcha The context object is not deeply merged; only top-level properties are available in preprocess directives. ↓

fix Pass nested values as flat keys or use a string expression that evaluates in the preprocess context.

Install

npm install rollup-plugin-preprocess

yarn add rollup-plugin-preprocess

pnpm add rollup-plugin-preprocess

Imports

default
wrong
```
const preprocess = require('rollup-plugin-preprocess').default
```
correct
```
import preprocess from 'rollup-plugin-preprocess'
```
This package uses a CommonJS default export; with ESM, import default directly. In CJS, use require('rollup-plugin-preprocess')() — note no .default.
RollupPluginPreprocess
wrong
```
import { RollupPluginPreprocess } from 'rollup-plugin-preprocess'
```
correct
```
import RollupPluginPreprocess from 'rollup-plugin-preprocess'
```
There is no named export; the entire module exports a single function. Using curly braces will result in undefined.

Quickstart

Shows how to configure the plugin with a context object and use preprocess directives in source files.

// rollup.config.js
import preprocess from 'rollup-plugin-preprocess';

export default {
  input: 'src/main.js',
  output: {
    file: 'dist/bundle.js',
    format: 'iife'
  },
  plugins: [
    preprocess({
      context: {
        DEBUG: process.env.DEBUG === 'true',
        VERSION: '1.0.0'
      }
    })
  ]
};

// In your source code:
// @if DEBUG
console.log('Debug mode');
// @endif
// @echo VERSION