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* Copyright 2009 Google Inc.
* 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
// Contents
The Closure Compiler performs checking, instrumentation, and
optimizations on JavaScript code. The purpose of this README is to
explain how to build and run the Closure Compiler.
The Closure Compiler requires Java 6 or higher.
// Building The Closure Compiler
There are three ways to get a Closure Compiler executable.
1) Use one we built for you.
Pre-built Closure binaries can be found at
2) Check out the source and build it with Apache Ant.
First, check out the full source tree of the Closure Compiler. There
are instructions on how to do this at the project site.
Apache Ant is a cross-platform build tool.
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
ant jar
This will produce a jar file called "build/compiler.jar".
3) Check out the source and build it with Eclipse.
Eclipse is a cross-platform IDE.
Under Eclipse's File menu, click "New > Project ..." and create a
"Java Project." You will see an options screen. Give the project a
name, select "Create project from existing source," and choose the
root of the checked-out source tree as the existing directory. Verify
that you are using JRE version 6 or higher.
Eclipse can use the build.xml file to discover rules. When you
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
// Running The Closure Compiler
Once you have the jar binary, running the Closure Compiler is straightforward.
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
You can read more detailed documentation about the many flags at
// Compiling Multiple Scripts
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. You
should check out the Closure Library. It contains functions for
enforcing dependencies between scripts, and a tool called
that knows how to give scripts to the Closure Compiler in the right
// Licensing
Unless otherwise stated, all source files are licensed under
the Apache License, Version 2.0.
Code under:
Version: 1.5R3, with heavy modifications
License: Netscape Public License and MPL / GPL dual license
Description: A partial copy of Mozilla Rhino. Mozilla Rhino is an
implementation of JavaScript for the JVM. The JavaScript parser and
the parse tree data structures were extracted and modified
significantly for use by Google's JavaScript compiler.
Local Modifications: The packages have been renamespaced. All code not
relavant to parsing has been removed. A JSDoc parser and static typing
system have been added.
Code in:
Version: Trunk
License: Netscape Public License and MPL / GPL dual license
Description: Mozilla Rhino is an implementation of JavaScript for the JVM.
Local Modifications: None. We've used JarJar to renamespace the code
post-compilation. See:
Code in:
Version: Trunk
License: Apache License 2.0
Description: Google's core Java libraries.
Local Modifications: None.
Code in:
Version: 3.8.1
License: Common Public License 1.0
Description: A framework for writing and running automated tests in Java.
Local Modifications: None.
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