gem-hunter

Conditional compilation and compile-time variable replacement for Rollup.

rollup-plugin-jscc is not a transpiler, it is a wrapper of jscc, a tiny and powerful, language agnostic file preprocessor that uses JavaScript to transform text based on expressions at compile time.

With jscc, you have:

• Conditional inclusion/exclusion of blocks, based on compile-time variables*
• Compile-time variables with all the power of JavaScript expressions
• Replacement of variables in the sources, by its value at compile-time
• Sourcemap support, useful for JavaScript sources.
• TypeScript v3 definitions

* This feature allows you the conditional declaration of ES6 imports (See the example).

Since jscc is a preprocessor, rollup-plugin-jscc is implemented as a file loader, so it runs before any transpiler and is invisible to them. This behavior allows you to use it in a wide range of file types but, if necessary, it can be used as a Rollup transformer instead of a loader.

NOTE

The removal of non-jscc comments is not included, but you can use rollup-plugin-cleanup, which brings compaction and normalization of lines in addition to the conditional removal of JS comments.

I'm a full-stack developer with more than 20 year of experience and I try to share most of my work for free and help others, but this takes a significant amount of time, effort and coffee so, if you like my work, please consider...

Of course, feedback, PRs, and stars are also welcome 🙃

Thanks for your support!

npm i rollup-plugin-jscc -D
# or
yarn add rollup-plugin-jscc -D

rollup-plugin-jscc requires rollup v2.0 and node.js v10.12 or later.

rollup.config.js

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

export default {
  input: 'src/main.js',
  plugins: [
    jscc({
      values: { _APPNAME: 'My App', _DEBUG: 1 },
    }),
  ],
  //...other options
}

in your source:

/*#if _DEBUG
import mylib from 'mylib-debug';
//#else */
import mylib from 'mylib'
//#endif

mylib.log('Starting $_APPNAME v$_VERSION...')

output:

import mylib from 'mylib-debug'

mylib.log('Starting My App v1.0.0...')

That's it.

* jscc has two predefined memvars: _FILE and _VERSION, in addition to giving access to the environment variables through the nodejs proccess.env object.

Plain JavaScript object, with all properties optional.

Please see the jscc wiki to know about directives used by jscc.

Please see the CHANGELOG.

The MIT License