# r.js

A command line tool for running JavaScript scripts that use the
[Asychronous Module Defintion API (AMD)](https://github.com/amdjs/amdjs-api/blob/master/AMD.md)
for declaring and using JavaScript modules and regular JavaScript script files.

It is part of the [RequireJS project](http://requirejs.org), and works with
the RequireJS implementation of AMD.

r.js is a single script that has two major functions:

* Run AMD-based projects [in Node](http://requirejs.org/docs/node.html) and Nashorn, Rhino and xpcshell.
* Includes the [RequireJS Optimizer](http://requirejs.org/docs/optimization.html)
that combines scripts for optimal browser delivery.

# Installation

## Node

    npm install -g requirejs

From then on, you can use `r.js` on the command line to run the optimizer.

## Nashorn/Rhino/Browser

Download the latest release from the
[RequireJS download page](http://requirejs.org/docs/download.html#rjs).

## xpcshell

[xpcshell](https://developer.mozilla.org/en-US/docs/XPConnect/xpcshell) support
was added in r.js version 2.1.5, so use that r.js version or later.

Download the latest release of r.js from the
[RequireJS download page](http://requirejs.org/docs/download.html#rjs).

## From this repo

r.js is made up of a series of modules that are built into one file for
distribution. The **dist** directory contains the built version of the
code. In the master branch, it should match the current state of the master
code.

If you are doing local modifications from a clone of this repo, you can run
the following command to generate an r.js at the root of this repo:

    node dist.js

To generate an r.js that also gets copied to **dist** with a time stamp, run:

    ./copydist.js

# Running AMD-based projects

If your JS project's main application file is called main.js, then do
the following:

## Node

    r.js main.js

Requires Node 0.4 or later.

r.js allows using Node modules installed via npm. For more info see the
[Use with Node](http://requirejs.org/docs/node.html) docs.

## Java

### Nashorn

As of r.js 2.1.16, r.js can run in [Nashorn](http://www.oracle.com/technetwork/articles/java/jf14-nashorn-2126515.html), Java 8+'s JavaScript engine, via the `jjs` command line tool that is installed with Java.

Then general format of the command:

```
jjs -scripting path/to/r.js -- [r.js command line arguments here]
```

Examples:

```
# Calling r.js to optimize a project using the build config in build.js
jjs -scripting path/to/r.js -- -o build.js

# Calling r.js to run AMD modules, where the main app program is main.js
jjs -scripting path/to/r.js -- main.js

```

All further examples will use the Node notation, but substitute the **r.js** references below with the command line structure mentioned above (`jjs -scripting path/to/r.js -- `).

### Rhino

Using Rhino requires some JAR files in the CLASSPATH for it to work:

* [rhino.jar](https://github.com/jrburke/r.js/blob/master/lib/rhino/js.jar?raw=true) from the [Rhino project](http://www.mozilla.org/rhino/).
* [compiler.jar](https://github.com/jrburke/r.js/blob/master/lib/closure/compiler.jar?raw=true) if you are using the optimizer and want to use
[Closure Compiler](http://code.google.com/closure/compiler/).

Download those files to your machine. To run r.js, you can use this type of
command:

### OS X/Linux/Unix:

    java -classpath path/to/rhino/js.jar:path/to/closure/compiler.jar org.mozilla.javascript.tools.shell.Main r.js main.js

### Windows

    java -classpath path/to/rhino/js.jar;path/to/closure/compiler.jar org.mozilla.javascript.tools.shell.Main r.js main.js

If you want to run it in the debugger, replace
org.mozilla.javascript.tools.shell.Main with
**org.mozilla.javascript.tools.debugger.Main**.

All further examples will use the Node notation, but substitute the **r.js** references below with the appropriate java command.

## xpcshell

To run the optimizer using a build config file or command line build options:

    path/to/xpcshell path/to/r.js -o buildconfig.js

r.js can also be used as a library in another .js file run via xpcshell.

* [tests/xpcshell/run.js](https://github.com/jrburke/r.js/blob/master/tests/xpcshell/run.js):
shows how to load AMD modules by using r.js as a library.
* [tests/xpcshell/build.js](https://github.com/jrburke/r.js/blob/master/tests/xpcshell/build.js):
shows how to trigger the optimizer from within another .js file.

# Optimizer

The optimizer can be run by passing the **-o** command to r.js:

    r.js -o path/to/buildconfig.js

See the [Optimization doc](http://requirejs.org/docs/optimization.html) for more
information on the optimizer.

If running in **Java**, be sure to grab the Rhino and Closure Compiler jar files in the lib/ directory, then run this command:

### OS X/Linux/Unix:

    java -classpath path/to/rhino/js.jar:path/to/closure/compiler.jar org.mozilla.javascript.tools.shell.Main r.js -o path/to/buildconfig.js

### Windows

    java -classpath path/to/rhino/js.jar;path/to/closure/compiler.jar org.mozilla.javascript.tools.shell.Main r.js -o path/to/buildconfig.js


## What makes it special

The optimizer is better than using a plain concatenation script because it runs
require.js as part of the optimization, so it knows how to:

* Use [Loader Plugins](http://requirejs.org/docs/plugins.html) to load non-script
dependencies and inline them in built files.
* [Name anonymous modules](http://requirejs.org/docs/api.html#modulename).
If your optimization step does not do this, and you use anonymous modules, you
will get errors running the built code.

# Other r.js commands

## Get Version

To get the version of r.js and the version of require.js used by r.js:

    r.js -v

## Convert CommonJS modules

To convert a directory of CommonJS modules to ones that have define() wrappers:

    r.js -convert path/to/commonjs/dir output/dir

Most, but not all, CommonJS modules can be converted to define()-wrapped modules
and still work.

However, there are some modules that may fail if:

* They use code branches like if/else or try/catch to call require(). There are
problems supporting this kind of dynamic module calls in an async environment.
* Some kinds of circular dependencies will not work right. The kinds that fail
are normally very brittle and depend on the execution order of the dependent
modules.

# Directory layout

## Directory prerequisites

r.js assumes that there are some other projects checked out as sibling
directories to it, and named certain names, in order for the tests to pass.

So it is best to create the following directory structure with the following
git clone commands:

    mkdir requirejs
    cd requirejs
    git clone git://github.com/jrburke/r.js.git
    git clone git://github.com/jrburke/requirejs.git
    git clone git://github.com/requirejs/text.git

So there should be a sibling `requirejs` and `text` directories to the r.js
directory containing your clone of the r.js project.

## Directory details

The r.js project has the following directory layout:

* **dist.js**: the script that builds r.js
* **require.js**: the version of require.js to include in r.js
* **dist** the directory containing releases of r.js
* **build**: The files that make up the optimizer. dist.js includes a list of
the files from this directory to build into r.js.
* **lib**: The Java libraries for Rhino and Closure Compiler. Only needed if using
Java/Rhino to run r.js
* **tests**: command line tests. Run it under Node and Rhino by doing ../r.js all.js

dist.js takes the build/jslib/x.js file and injects the require.js files and other
files from the build/jslib directory into it.

If you make changes to any of those files, you will need to run **node dist.js**
to generate a new r.js. Be sure to run it through the tests , using both Node
and Java/Rhino:

    * node dist.js
    * cd tests
    * node ../r.js all.js
    * java -classpath ../lib/rhino/js.jar:../lib/closure/compiler.jar org.mozilla.javascript.tools.shell.Main ../r.js all.js
    * cd ../build/tests
    * node ../../r.js all.js
    * java -classpath ../../lib/rhino/js.jar:../../lib/closure/compiler.jar org.mozilla.javascript.tools.shell.Main ../../r.js all.js

For running tests, put xpcshell in env/xpcshell/ as a directory, that contains
all the files needed for it to run, including the xpcshell binary. Downloading
[a xulrunner nightly](http://ftp.mozilla.org/pub/mozilla.org/xulrunner/nightly/latest-mozilla-central/)
might work.

# Contributing code changes

See the [RequireJS Contributing](http://requirejs.org/docs/contributing.html)
page for info on how to contribute code/bug fixes to this project.

Use GitHub pull requests to point to code changes, although for larger changes,
contact the [requirejs mailing list](http://groups.google.com/group/requirejs)
to discuss them first.

# Included libraries

r.js includes modules from these projects:

* [Esprima](http://esprima.org/)
* [UglifyJS](https://github.com/mishoo/UglifyJS)

# Doing a release

To do a release of version 0.0.0:

* Make sure the right version of require.js is in the project.
* Modify build/jslib/x.js to update the r.js version number in two places.
* node dist.js
* Run the tests (see above). They should pass. :)
* mv r.js dist/r.js
* git commit -am "Release 0.0.0"
* git tag -am "Release 0.0.0" 0.0.0
* git push origin master
* git push --tags

Update the RequireJS download site to point to the latest release, then update
the [requirejs/requirejs-npm](https://github.com/requirejs/requirejs-npm) repo to have the latest
changes and publish the result to npm.

Make sure to keep `#!/usr/bin/env node` as the first line in bin/r.js in
the requirejs-npm repo.
