rollup-preserve-directives

1.1.3 verified Mon Apr 27 auth: no javascript

Rollup plugin to preserve shebang and string directives (e.g., 'use strict') in bundled output. Current stable version 1.1.3, maintained actively. No external dependencies, ships TypeScript types. Key differentiator: handles shebang and directives that Rollup's tree-shaking may remove, and exposes metadata for inter-plugin communication. Renamed from rollup-swc-preserve-directives in v1.0.0.

Common errors

error SyntaxError: Unexpected token 'export' ↓

cause Using require() to import an ES module package.

fix

Use import syntax or rename config file to .mjs.

error Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'rollup-preserve-directives' ↓

cause Package not installed or mismatched version.

fix

Run npm install rollup-preserve-directives.

error TypeError: preserveDirectives is not a function ↓

cause Default import error, possibly using named import instead of default.

fix

Use import preserveDirectives from 'rollup-preserve-directives' (default import).

Warnings

breaking Package renamed from rollup-swc-preserve-directives to rollup-preserve-directives in v1.0.0. Old package deprecated. ↓

fix Uninstall old package: npm uninstall rollup-swc-preserve-directives. Install new: npm install rollup-preserve-directives. Update import.

breaking v1.0.0 dropped dependency on swc/core. Plugin now uses Rollup's built-in parser only. ↓

fix No change needed unless you relied on swc-specific behavior. Remove any swc options from plugin call.

deprecated v0.x versions (under old name rollup-swc-preserve-directives) are deprecated and receive no updates. ↓

fix Upgrade to v1.0.0+ and rename package.

gotcha Plugin only works with Rollup's ESM configuration files (rollup.config.mjs or type: module). ↓

fix Ensure your config file uses ES module syntax (export default) and has .mjs extension or package.json type: module.

gotcha May not preserve directives in all cases; if you rely on specific directives being kept, verify output. ↓

fix Use this.getModuleInfo or moduleParsed hook to check directives metadata.

Install

npm install rollup-preserve-directives

yarn add rollup-preserve-directives

pnpm add rollup-preserve-directives

Imports

default

wrong

const preserveDirectives = require('rollup-preserve-directives')

correct

import preserveDirectives from 'rollup-preserve-directives'

ESM-only package; CJS require is not supported.

type PreserveDirectivesOptions

import type { PreserveDirectivesOptions } from 'rollup-preserve-directives'

Type import for TypeScript users only.

type PluginMeta
```
import type { PluginMeta } from 'rollup-preserve-directives'
```
Type for the metadata exposed via moduleParsed hook.

Quickstart

Basic rollup.config.js configuration showing how to use the plugin to preserve shebang and directives.

import preserveDirectives from 'rollup-preserve-directives';

export default {
  input: './src/index.js',
  output: {
    file: './dist/index.js',
    format: 'cjs',
  },
  plugins: [
    preserveDirectives(),
  ],
};