Neha Patil (Editor)

Google Closure Tools

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Original author(s)
  
Google

Stable release
  
20160822

Type
  
Ajax framework

Initial release
  
November 5, 2009

Available in
  
JavaScript

License
  
Apache License 2.0

Google Closure Tools is a set of tools to help developers build rich web applications with JavaScript. It was developed by Google for use in their web applications such as Gmail, Google Docs and Google Maps.

Contents

Closure Compiler

The Closure Compiler is a tool for making JavaScript download and run faster, at the expense of human readability. It does not compile from JavaScript to machine code, but rather compiles from JavaScript to more efficient JavaScript. It parses JavaScript, analyzes it, removes dead code and rewrites and minifies what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It supports transpiling some ECMAScript 6 code to ECMAScript 3, so that programmers can write JavaScript that uses those features, and run it in browsers or other environments that don't yet support them. (The Traceur Compiler is another Google project that supports transpiling ES6 to ES3.) Closure source code can be compiled in three ways:

  • From the command line:
  • Java application that can be passed the list of JavaScript files to be compiled.
  • npm package google-closure-compiler-js (no Java dependencies)
  • Interactively in the browser:
  • The Closure Compiler service website provides a form for a user to input a URL pointing to a JavaScript source or enter JavaScript source code in a textbox. The website will display with the optimized JavaScript on right side for the user to copy.
  • HTTP POST API:
  • The Closure Compiler server accepts HTTP POST requests. Parameters include the string of JavaScript to be optimized (or a URL pointing to it), the optimization level, whether to include errors and warnings, and the output format (JSON, XML, or text).

    • The Closure compiler also supports type checking via type annotations that must be written in JSDoc comments.

    Ecosystem

    Programming languages that transpile to JavaScript benefit from Closure Tools. For example, Closure Compiler helps to make ClojureScript practical by making the compiled JavaScript code more efficient.

    Closure Library

    The Closure Library is a JavaScript library, written specifically to take advantage of the Closure Compiler, based on a modular architecture. It provides cross-browser functions for DOM manipulations and events, Ajax and JSON, as well as more high-level objects such as User Interface widgets and Controls.

    Closure Templates

    Closure Templates are a templating system for dynamically generating HTML in both Java and JavaScript.

    Because the language was apparently referred to as "Soy" internal to Google, and "Soy" remains in some of the documentation and classes, sometimes Closure Templates are referred to as "Soy Templates".

    Closure Stylesheets

    This is a compiler which provides an extended version of CSS, which is compiled down to ordinary CSS. Internally in Google, this extended version of CSS is referred to as GSS.

    References

    Google Closure Tools Wikipedia
    (Text) CC BY-SA