rollup-plugin-jscc

2.0.0 verified Mon Apr 27 auth: no javascript maintenance

Rollup plugin for conditional compilation and compile-time variable replacement using jscc. Current stable version is 2.0.0, released 2020-08-28, with a maintenance cadence (last major release). Key differentiators: runs before transpilers as a file loader (or optionally as transformer), supports TypeScript definitions, sourcemaps, and uses full JavaScript expressions for conditional blocks. Unlike other preprocessors, it is language agnostic and tightly integrated with Rollup v2+, requiring Node >=10.12.0.

Common errors

error Error: RollupError: Could not resolve './some-module' from src/main.js ↓

cause Conditional import not excluded because the preprocessor directive is incorrectly placed or missing.

fix

Ensure conditional blocks use correct jscc syntax, e.g., /*#if _DEBUG ... //#else ... //#endif*/

error TypeError: Cannot read property 'unset' of undefined ↓

cause Using an older version of jscc that lacks certain features or using incorrect variable names.

fix

Update to rollup-plugin-jscc v2.0.0 and ensure variable names match pattern /^_[0-9A-Z][_0-9A-Z]*$/.

error SyntaxError: Invalid or unexpected token ↓

cause Directives like //#if not recognized because the prefix does not match default (default: ['//', '/*', '<!--']).

fix

Set 'prefixes' option to include your chosen comment prefix, e.g., prefixes: ['//#', '/*#'].

Warnings

breaking Requires Rollup v2 and Node.js >=10.12.0. Older versions of rollup-plugin-jscc (v1.x) were compatible with Rollup v1. ↓

fix Update Rollup to v2+ and Node.js to >=10.12.0.

deprecated The asloader option is deprecated. Use the default loader behavior instead. ↓

fix Remove 'asloader' option from plugin config.

gotcha Variable names must match regex /^_[0-9A-Z][_0-9A-Z]*$/. Predefined variables like _FILE and _VERSION are automatically available. ↓

fix Use uppercase names starting with underscore for custom variables.

gotcha The removal of non-jscc comments is not supported. Use rollup-plugin-cleanup if needed. ↓

fix Add rollup-plugin-cleanup to remove JavaScript comments.

breaking v2.0.0 removed support for CommonJS output from the plugin itself; it only provides ESM. ↓

fix Use 'import' syntax to include the plugin in your rollup config.

Install

npm install rollup-plugin-jscc

yarn add rollup-plugin-jscc

pnpm add rollup-plugin-jscc

Imports

jscc
wrong
```
const jscc = require('rollup-plugin-jscc')
```
correct
```
import jscc from 'rollup-plugin-jscc'
```
Package is ESM-only since v2.0.0. Default export is the plugin function.

jscc

wrong

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

correct

import jscc from 'rollup-plugin-jscc'

There is no named export; only a default export.

type JsccOptions

wrong

import { JsccOptions } from 'rollup-plugin-jscc'

correct

import type { JsccOptions } from 'rollup-plugin-jscc'

Use import type for TypeScript types to avoid runtime errors.

Quickstart

Basic setup: use jscc with custom values and conditional compilation. Shows default export and directive syntax.

// rollup.config.js
import jscc from 'rollup-plugin-jscc'

export default {
  input: 'src/main.js',
  output: { file: 'dist/bundle.js', format: 'esm' },
  plugins: [
    jscc({
      values: {
        _APPNAME: 'My App',
        _DEBUG: process.env.DEBUG ? 1 : 0
      }
    })
  ]
}

// src/main.js
/*#if _DEBUG
console.log('Debug mode');
//#else
console.log('Release mode');
//#endif*/
console.log('$_APPNAME v$_VERSION');

/* Output when DEBUG is truthy:
console.log('Debug mode');
console.log('My App v2.0.0');
*/