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 -Drollup-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
