# Asset Smasher Asset pre-processor, merger, and compressor for Node.js - [Structuring Your Assets](#structure-assets) - [Manifest Files](#manifest-files) - [Manifest Directories](#manifest-directories) - [Using via Command Line](#command-line) - [Helpers](#cli-helpers) - [Plugins](#cli-plugins) - [Using via Express Middleware](#express-middleware) - [Using via Programmatic Interface](#programmatic-interface) - [Transformer Notes](#transformer-notes) - [AMD Support](#tn-amd) - [LESS/Stylus](#tn-less-styl) - [ejs](#tn-ejs) - [dust and Handlebars](#tn-dust-hbs) ## Overview Asset Smasher is a command-line tool, express middleware, and programmatic interface for: - Pre-processing and transforming files down to plain JavaScript and CSS. - `.coffee` - Compile [CoffeeScript](http://coffeescript.org/) into JavaScript - `.ejs` - Run a file through [EJS](https://github.com/visionmedia/ejs) (e.g. to populate configuration parameters into a JavaScript file) - `.less` - Compile [Less](http://lesscss.org/) into CSS - `.styl` - Compile [Stylus](http://learnboost.github.io/stylus/) into CSS - `.hbs` - Precompile [Handlebars](http://handlebarsjs.com/) templates into JavaScript files that register them with `Handlebars.templates`. - `.dust` - Precompile [Dust](http://linkedin.github.io/dustjs/) templates into JavaScript files that register them for use with `dust.render`. - `.jsx` - Transform JSX files (for use with [React](http://facebook.github.io/react/)) into JavaScript files. - Can wrap CommonJS-style JavaScript files with [AMD](https://github.com/amdjs/amdjs-api/wiki/AMD) `define` calls. - Processors can be chained together. E.g `test.js.hbs.ejs` (run Handlebars template through EJS, then compile it) - Additional processors can be plugged in. - Merging files together using Manifest files (`.mf`) with dependency management directives similar to Sprockets. - `require` - Require a single file - `require_dir` - Require all the files in a specific directory - `require_tree` - Require all the files in a specific directory (and subdirectories) - Compressing, gzipping, and generating hashed file names. - Compress JavaScript files with `uglify-js` - Compress CSS files with `ycssmin` - Generate Gzipped versions of files - Include a MD5 hash of the file's contents in the file name. `myAsset.js` -> `myAsset-c89cba7b7df028e65cb01d86f4d27077.js` - `asset_path` helper that can be used to reference the hashed name. It's released under the [MIT](http://en.wikipedia.org/wiki/MIT_License) license. ## Structuring Your Assets Asset Smasher has the concept of "asset paths". These are locations in which your asset files will be located, and from which any relative asset paths will be rooted to. The simplest structure has one asset path. E.g. Asset Paths ----------- - app File Structure -------------- app/ js/ css/ images/ A more complicated structure might be Asset Paths ----------- - app - lib - vendor File Structure -------------- app/ js/ css/ images/ lib/ js/ css/ images/ vendor/ js/ css/ images/ Both of these examples will result in a compiled structure of js/ css/ images/ ### Manifest Files Manifest (`.mf`) files are used to merge many assets into a single resulting file. The file should be named with the resulting file type before the `.mf` extension (e.g. `manifest.css.mf` or `manifest.js.mf`. *Manifest files can `require` other manifest files* Only files that will be transformed down to a file of a manifest's "type" (e.g. `manifest.css.mf` => `.css`, `manifest.js.mf` => `.js`) will be included. This means that, for example, if you `require_dir` a directory in a JavaScript manifest that happens to contain both JavaScript and CSS, only the JavaScript files will be required. A simple manifest file might look like # A comment here require "./one.js" require_dir "./subdir1" # # Another comment require_tree "./subdir2" **Directives:**

Directive	Description
`require "[path]"`	Include a single file If the path starts with `"/"`, `"../"`, or `"./"`, process and include the specified file. The file must be inside one of the configured asset paths. If the path does not start with `"/"`, `"../"`, or `"./"`, the file will be searched for in all of the configured asset paths. E.g. if there are asset paths `one` and `two` defined, `require "js/test.js"` will look for `one/js/test.js` and then `two/js/test.js` stopping when it finds a matching file. The filename part of the path does not have to include the whole extension. E.g `require "test"` finds the first file that matches the name in the asset paths (for example `test.js.ejs`) If the file does not exist/can't be resolved/isn't of the right type for the manifest, it will be ignored (will be logged in verbose mode).
`require_dir "[path]"`	Include all the files in a directory The path must be absolute, or relative to the current directory. E.g. you can do `require_dir "../some/other/dir"` but not `require_dir "somedir"` If using absolute paths, or `".."` in your paths, the resulting directory needs to be inside one of the configured asset paths. If the directory does not exist, it will be ignored (will be logged in verbose mode).
`require_tree "[path]"`	Include the files in a directory recursively The rules for `require_tree` are the same as the rules for `require_dir`

### Manifest Directories If you create a directory, for example named `foo.js.mf` and put a bunch of javascript files in it (or any subdirectories under it), `asset-smasher` will (recursively) take all the files inside and merge them into `foo.js`. Essentially, this is a time-saver so that you don't have to create a manifest file that only contains a single `require_tree` directive. ## Using via Command-Line Use `npm install -g asset-smasher` to install the `asset-smasher` command-line tool globally. asset-smasher --help Usage: asset-smasher [options] Options: -h, --help output usage information -V, --version output the version number --compress compress/minify the generated files --hash generate versions of the files with md5 hashes in the name --gzip generate gzipped versions of the compiled files --hashVersion invalidate all assets without changing file contents [1.0] --only only process the files matching these glob patterns (relative to any of the paths) [**/*.*] --paths list of paths to look for assets [.] --prefix prefix to append to logical paths when constructing urls. use if output dir is not served from the root of your web app [] --helpers a .js module of helper functions require()s to expose to transforms [] --plugins a .js plugin module [] --amd enable AMD support (give anonymous modules names, support /** @amd */ pragma comments) --verbose output more verbose information about what is going on to the console --noclean do not delete the output directory before generating files (by default it will be removed first) If --only is not specified, *all* files in the --paths will be processed. If --hash is specified, a map.json file will be generated that maps the unmangled file name to the hashed one. Be careful that your shell doesn't expand glob patterns when passing them as arguments. To be safe, surround the argument with quotes. Examples: Compile all assets in the current directory to /home/me/compiledAssets $ asset-smasher /home/me/compiledAssets Something similar to what the Rails asset pipeline does by default $ asset-smasher --compress --hash --gzip --prefix /assets \ --paths ./js,./css,./images \ --only "**/*.jpg,**/*.gif,**/*.png,application.js.mf,application.css.mf" ./public/assets Compile assets, providing some custom helpers to the transformation $ asset-smasher --helpers helpers.js output ### Helpers There is a built-in `asset_path` helper that can be used to get the "real" (i.e. with hashed file name) path of an asset. E.g. `asset_path('css/myFile.css')` might return `'/assets/css/myFile-c89cba7b7df028e65cb01d86f4d27077.css`. Some transformers (e.g. the `.ejs` one) take in a set of local variables that they can use during transformation. You can pass in the path to a JavaScript module whose exports will be included in this set of variables. You can use this, for example, to set configuration parameters in your JS files: **helper.js** exports.serviceUrl = 'http://my.service/'; **config.js.ejs** //... var serviceUrl = '<%= serviceUrl %>'; var cssLocation = '<%= asset_path('css/myFile.css') %>'; //... **Execution** $ asset-smasher --helpers helper.js --only config.js.ejs,css/myFile.css . $ cat config.js var serviceUrl = 'http://my.service/'; var cssLocation = '/assets/css/myFile-c89cba7b7df028e65cb01d86f4d27077.css'; ### Plugins If there's a type of file you want to pre-process that is not natively supported by Asset Smasher, you can add it using a plugin file. For an example of what the transformer classes look like, look in the `lib/compilation/transforms` directory If a plugin module is passed (via `--plugins`), it will be `require()`d and then invoked, being passed in the asset smasher library (the module defined in `lib/asset-smasher.js`) To register your transformer, just add another entry to the `transforms` object. E.g. **my_plugin.js** module.exports = function(assetSmasher) { // A stupid transformer that adds "foo" to the start and end of the contents var FooTransform = function FooTransform(options) { this.options = options || {}; }; FooTransform.prototype = { extensions:function () { return ['.foo']; }, shouldTransform:function (file) { return path.extname(file) === '.foo'; }, transformedFileName:function (file) { return path.basename(file, '.foo'); }, transform:function (asset, cb) { // Transform the file name asset.logicalName = this.transformedFileName(asset.logicalName); // Get the contents var contents = asset.contents; if (Buffer.isBuffer(contents)) { contents = contents.toString('utf-8'); } // Compile the contents asset.contents = 'foo-' + contents + '-foo'; cb(); } }; assetSmasher.transforms.Foo = FooTransform; }; If you then invoke `asset-smasher` with `--plugins my_plugin.js` it will automatically transform `*.foo` files. ## Using via Express Middleware Asset smasher exposes an `express` middleware that can: - Serve your assets un-merged/mangled in development mode. - Serve precompiled assets (with hashed file names) in production mode. The middleware takes in the same arguments as the `Smasher` constructor, with a few extras: - `serve` - boolean (or object - see more below) indiacating whether the middleware should serve the asset files. Usualy set this to `true` in development, `false` in production (e.g if you're using precompiled assets) - An object can be passed in with the following properties to control the serving behavior. If `true` is passed in, the default values here will be used - `individual` - Whether the individual (`true`) or merged files (`false`) should be served. Default `true`. - `assetMapLocation` - path to the `map.json` generated by the command-line `asset-smasher` util. This allows the helper methods to determine what the hashed file names were The middleware exposes two helpers to your views: - `js_asset(logicalPath)` - Render a `