The Closure Compiler performs checking, instrumentation, and optimizations on JavaScript code.

1. Ensure that you have Java 7 installed.

2. Download the [Closure Compiler] (https://code.google.com/p/closure-compiler/wiki/BinaryDownloads?tm=2).

3. Run the following command from the command line to compile a JavaScript file:

   java -jar compiler.jar --js hello.js --js_output_file hello-compiled.js
   

Read the [documentation] (http://code.google.com/closure/compiler/docs/gettingstarted_app.html) to learn more about how to use the Closure Compiler.

Note: The Closure Compiler requires Java 7 or higher.

1. Download the Ant build tool.

2. At the root of the source tree, there is an Ant file named build.xml. To use it, navigate to the same directory and type the command

   ant jar
   

   This will produce a jar file called build/compiler.jar.

1. Download and open the Eclipse IDE.
2. Navigate to File > New > Project ... and create a Java Projet. Give the project a name.
3. Select Create project from existing source and choose the root of the checked-out source tree as the existing directory.
4. Navigate to the build.xml file. You will see all the build rules in the Outline pane. Run the jar rule to build the compiler in build/compiler.jar.

On the command line, type

java -jar compiler.jar

This starts the compiler in interactive mode. Type

var x = 17 + 25;

then hit "Enter", then hit "Ctrl-Z" (on Windows) or "Ctrl-D" (on Mac or Linux) and "Enter" again. The Compiler will respond:

var x=42;

The Closure Compiler has many options for reading input from a file, writing output to a file, checking your code, and running optimizations. To learn more, type

java -jar compiler.jar --help

More detailed information about running the Closure Compiler is available in the documentation.

If you have multiple scripts, you should compile them all together with one compile command.

java -jar compiler.jar --js=in1.js --js=in2.js ... --js_output_file=out.js

The Closure Compiler will concatenate the files in the order they're passed at the command line.

If you need to compile many, many scripts together, you may start to run into problems with managing dependencies between scripts. In this case, you should use the Closure Library. It contains functions for enforcing dependencies between scripts, and a tool called calcdeps.py that knows how to give scripts to the Closure Compiler in the right order.

Copyright 2009 The Closure Compiler Authors.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Two copies of Rhino exist in this repository: