rollup-plugin-jscc

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.

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Install

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.

Usage

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.

Options

Plain JavaScript object, with all properties optional.

| Name | Type | Description | | --- | --- | --- | | asloader | boolean | If false, run the plugin as a transformer, otherwise run as loader (the default). | | escapeQuotes | string | String with the type of quotes to escape in the output of strings: 'single', 'double' or 'both'.Default nothing. | | keepLines | boolean | Preserves the empty lines of directives and blocks that were removed.Use this option with sourceMap:false if you are interested only in keeping the line numbering.Default false | | mapHires | boolean | Make a hi-res source-map, if sourceMap:true (the default).Default true | | prefixes | string | RegExp |Array<string|RegExp> | The start of a directive. That is the characters before the '#', usually the start of comments.Default ['//', '/*', '<!--'] (with one optional space after them). | | sourcemap | boolean | Must include a sourcemap?Should be the same value as the property sourcemap of the Rollup output.Default true | | mapContent | boolean | Include the original source in the sourcemap, if sourceMap:true (the default).Default true | | values | object | Plain object defining the variables used by jscc during the preprocessing.Default {} | | extensions | string | Array<string> | Array of strings that specifies the file extensions to process.Default ['js', 'jsx', 'ts', 'tsx', 'mjs', 'tag'] | | include | string | Array<string> | minimatch or array of minimatch patterns for paths that must be included in the processing. | | exclude | string | Array<string> | minimatch or array of minimatch patterns for paths that should be ignored. |

Directives

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

What's New

Please see the CHANGELOG.

License

The MIT License