# Rainbow Rainbow is a code syntax highlighting library written in Javascript. It was designed to be lightweight (~2.5kb), easy to use, and extendable. It is completely themable via CSS. ## Demo You can see rainbow in action at [http://rainbowco.de](http://rainbowco.de). You can also build/download custom packages from there. ## Contents * [Quick Start](#quick-start) * [Browser](#browser) * [Node.js](#nodejs) * [Install rainbow](#install-rainbow) * [Highlight some code](#highlight-some-code) * [Supported Browsers](#supported-browsers) * [Supported Languages](#supported-languages) * [Specifying a language](#specifying-a-language) * [Themes](#themes) * [Rendering code blocks](#rendering-code-blocks) * [Adding custom rules for specific languages](#adding-custom-rules-for-specific-languages) * [JavaScript API Documentation](#javascript-api-documentation) * [Rainbow.color](#rainbowcolor) * [Preventing automatic highlighting on page load](#preventing-automatic-highlighting-on-page-load) * [Extra options for color](#extra-options-for-color) * [globalClass](#globalclass) * [Rainbow.extend](#rainbowextend) * [Extending existing languages](#extending-existing-languages) * [How code is highlighted](#how-code-is-highlighted) * [Match by name](#match-by-name) * [Match by group](#match-by-group) * [Match by array of sub-patterns](#match-by-array-of-sub-patterns) * [Match using another language](#match-using-another-language) * [Extending an existing language](#extending-an-existing-language) * [How Rainbow chooses a match](#how-rainbow-chooses-a-match) * [Known limitations](#known-limitations) * [Regular expressions lookbehind assertions](#regular-expressions-lookbehind-assertions) * [Regular expression subgroup matches](#regular-expression-subgroup-matches) * [Rainbow.addAlias](#rainbowaddalias) * [Rainbow.onHighlight](#rainbowonhighlight) * [Rainbow.remove](#rainbowremove) * [Building](#building) * [Getting a local environment set up](#getting-a-local-environment-set-up) * [Build commands](#build-commands) * [gulp build](#gulp-build) * [gulp lint](#gulp-lint) * [gulp pack](#gulp-pack) * [gulp sass](#gulp-sass) * [gulp test](#gulp-test) * [gulp watch](#gulp-watch) * [More Info](#more-info) ## Quick Start ### Browser 1. Include some markup for code you want to be highlighted: ```html

def openFile(path):
        file = open(path, "r")
        content = file.read()
        file.close()
        return content

``` 2. Include a CSS theme file in the ````: ```html ``` 3. Include rainbow.js and whatever languages you want before the closing ````: ```html ``` By default `dist/rainbow.min.js` comes with some popular languages bundled together with it. ### Node.js Rainbow 2.0 introduced support for node.js. All of the existing API methods should work, but there is also a new `Rainbow.colorSync` method for synchronous highlighting. #### Install rainbow ``` npm install --save rainbow-code ``` #### Highlight some code ```javascript var rainbow = require('rainbow-code'); var highlighted = rainbow.colorSync('// So meta\nrainbow.colorSync(\'var helloWorld = true;\');', 'javascript'); console.log(highlighted); ``` ## Supported Browsers Rainbow 2.0 should work in the following browsers: | Chrome | Firefox | IE | Safari | | ------ | ------- | --- | ------ | | 20+ | 13+ | 10+ | 6+ | For older browsers you can download the legacy [1.2.0](https://github.com/ccampbell/rainbow/archive/1.2.0.zip) release. ## Supported Languages Currently supported languages are: - C - C# - Coffeescript - CSS - D - Go - Haskell - HTML - Java - JavaScript - JSON - Lua - PHP - Python - R - Ruby - Scheme - Shell - Smalltalk ## Specifying a language In your markup the `data-language` attribute is used to specify what language to use for highlighting. For example: ```html

var testing = true;

``` Rainbow also supports the HTML5 style for specifying languages: ```html

var testing = true;

``` And the Google prettify style: ```html

var testing = true;

``` ## Themes Themes are located in the `themes/sass` directory. They are written using sass so that common logic can be shared among all themes without having to duplicate it in each theme file. You should not edit the css files directly. `_base.sass` includes some default styles shared by almost every theme. `_init.sass` contains mixins and initialization logic that is shared by every theme. ### Rendering code blocks As of version 2.0 the themes use a clever trick to display the highlighted code. All code blocks default to `opacity: 0`, but an animation is triggered on page load to happen after a 2 second delay. This means for users who do not have JavaScript enabled the code will fade in after 2 seconds. If JavaScript is enabled, the animation is stopped on load and the delay is reset to `0s`. That ensures that as soon as the code is done being highlighted it will be able to show up instantly. This is used to prevent a flash of unstyled text on page load and ensure that the code blocks only show up after they have been highlighted. There is also a preload animation that will show up for any code block that takes longer than 300ms to load. ### Adding custom rules for specific languages A SASS mixin was added to simplify defining styles that should only apply for a specific language. Using it looks like this: ```sass @include language("html") .support.operator color: #fff @include language(("javascript", "js")) .variable.super color: #66D9EF ``` You can pass a single language or a list of languages. ## JavaScript API Documentation Rainbow has four public methods: - [Rainbow.color](#rainbowcolor) - [Rainbow.extend](#rainbowextend) - [Rainbow.addAlias](#rainbowaddalias) - [Rainbow.onHighlight](#rainbowonhighlight) - [Rainbow.remove](#rainbowremove) ### Rainbow.color Rainbow.color is used to highlight blocks of code. For convenience, this method is called automatically to highlight all code blocks on the page when `DOMContentLoaded` fires. If you would like to highlight stuff that is not in the DOM you can use it on its own. There are three ways to use it. 1. The first option is calling the color method on its own: ```javascript Rainbow.color(); ``` Each time this is called, Rainbow will look for matching `pre` blocks on the page that have not yet been highlighted and highlight them. You can optionally pass a callback function that will fire when all the blocks have been highlighted. ```javascript Rainbow.color(function() { console.log('The new blocks are now highlighted!'); }); ``` 2. The second option is passing a specific element to the color method. In this example we are creating a code block, highlighting it, then inserting it into the DOM: ```javascript var div = document.createElement('div'); div.innerHTML = '

var foo = true;

'; Rainbow.color(div, function() { document.getElementById('something-else').appendChild(div;) }); ``` 3. The final option is passing in your code as a string to `Rainbow.color`. ```javascript Rainbow.color('var foo = true;', 'javascript', function(highlightedCode) { console.log(highlightedCode); }); ``` #### Preventing automatic highlighting on page load If you want to prevent code on the page from being highlighted when the page loads you can set the `defer` property to `true`. ```javascript Rainbow.defer = true; ``` Note that you have to set this before `DOMContentLoaded` fires or else it will not do anything. #### Extra options for color As of right now there is one extra option for color. ##### globalClass This option allows you to have an extra class added to every span that Rainbow renders. This can be useful if you want to remove the classes in order to trigger a special effect of some sort. To apply a global class you can add it in your markup: ```html

var hello = true;

``` Or you can pass it into a `Rainbow.color` call like this: ```javascript Rainbow.color('var hello = true;', { language: 'javascript', globalClass: 'animate' }); ``` ### Rainbow.extend Rainbow.extend is used to define language grammars which are used to highlight the code you pass in. It can be used to define new languages or to extend existing languages. A very simple language grammer looks something like this: ```javascript Rainbow.extend('example', [ { name: 'keyword', pattern: /function|return|continue|break/g } ]); ``` Any pattern used with extend will take precedence over an existing pattern that matches the same block. It will also take precedence over any pattern that is included as part of the generic patterns. For example if you were to call ```javascript Rainbow.extend('example', [ { name: 'keyword.magic', pattern: /function/g } ]); ``` This would mean that function will be highlighted as `function`, but `return`, `continue`, and `break` will still be highlighted as just `return`, etc. #### Extending existing languages By default languages are considered to be standalone, but if you specify an optional third parameter you can have your language inherit from another one. For example the python language grammars inherit from the generic ones: ```javascript Rainbow.extend('python', [ { name: 'constant.language', pattern: /True|False|None/g } ], 'generic'); ``` If you wanted to remove the default boolean values you should be able to do something like this: ```javascript Rainbow.extend('python', [ { name: '', pattern: /true|false/g } ]); ``` #### How code is highlighted The `name` value determines what classes will be added to a span that matches the pattern you specify. For example, if you name a pattern `constant.hex-color` the code that matches that pattern will be wrapped in ` ``` You see the value class never gets applied. To achieve what you really want you would have to use a subpattern like this: ```javascript { name: 'name.attribute', matches: [{ matches: { 1: 'value' }, pattern: /\"(.*?)\"/g }], pattern: /(name=\"(.*?)\")/g } ``` This means the entire block is wrapped with `name.attribute` scope and then within that any part in double quotes will be wrapped as `value`. That means the entire block will behighlighted as ```html name="value" ``` In this example you could avoid subpatterns completely by using a regex like this to begin with: ```javascript /(name=)\"(.*?)\"/g ``` ### Rainbow.addAlias The addAlias function allows you to map a different name to a language. For example: ```javascript Rainbow.addAlias('js', 'javascript'); ``` This allows you to highlight javascript code by using the language `js` instead of `javascript`. ### Rainbow.onHighlight This method notifies you as soon as a block of code has been highlighted. ```javascript Rainbow.onHighlight(function(block, language) { console.log(block, 'for language', language, 'was highlighted'); }); ``` The first parameter returns a reference to that code block in the DOM. The second parameter returns a string of the language being highlighted. ### Rainbow.remove This method allows you to remove syntax rules for a specific language. It is only really useful for development if you want to be able to reload language grammars on the fly without having to refresh the page. ```javascript // Remove all the javascript patterns Rainbow.remove('javascript'); ``` ## Building Rainbow is compiled using [rollup](https://github.com/rollup/rollup) and [buble](https://gitlab.com/Rich-Harris/buble). [Gulp](https://github.com/gulpjs/gulp) is used for all build related tasks. ### Getting a local environment set up ```shell git clone git@github.com:ccampbell/rainbow.git cd rainbow npm install ``` ### Build commands #### gulp build The build command is used to build a custom version of rainbow.js. If you run ```shell gulp build ``` A file will be created at `dist/rainbow-custom.min.js` containing rainbow.js as well as popular languages. If you want to specify specific languages you can use: ```shell gulp build --languages=html,css,php,javascript ``` If you want a minimized version of rainbow without any languages you can pass ```shell gulp build --languages=none ``` If you want a minimized version with all languages you can pass ```shell gulp build --languages=all ``` #### gulp lint The lint command will check all the javascript files for things that do not match the styleguide from the `.eslintrc` file. #### gulp pack The pack command will run a buble + rollup build and save the resulting file to `dist/rainbow.js` #### gulp sass The sass command will compile all the rainbow themes #### gulp test The test command will run the unit tests. You can pass the `--watch` flag to keep the tests running and have them rerun when you make changes. That is a little buggy though which has something to do with karma + rollup. You can also use the `--browsers` flag to specify a browser to run the tests in. Currently only `PhantomJS` and `Chrome` are supported. #### gulp watch The watch command will look at sass files and src js files and build the css or js (using `gulp sass` and `gulp pack`) every time you make a change. ## More Info If you are looking for line number support you can try one of the following: - https://github.com/Blender3D/rainbow.linenumbers.js - https://github.com/Sjeiti/rainbow.linenumbers You can check out demos and build custom packages at [rainbowco.de](http://rainbowco.de).

	Stars	Issues	Version	Updated	Created
prism			4.1.2	7 years ago	11 years ago
rainbow-code	3,294	69	2.1.7	4 years ago	8 years ago
syntax-highlighter			0.0.3	8 years ago	8 years ago
syntaxhighlighter			4.0.1	8 years ago	10 years ago

prism vs rainbow-code vs syntax-highlighter vs syntaxhighlighter

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