Google Closure Library

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The up to date version of this page can be found at https://clojurescript.org/reference/google-closure-library

ClojureScript projects always auto-include the Google Closure Library, a massive library built and used by Google on many of their products (Gmail, Docs, etc). It has low-level utilities for DOM manipulation, server communication, animation, data structures, unit testing, rich-text editing, and UI widgets/controls.

• Google Closure Library API Reference
• Closure Cheatsheet - abridged API with usage examples

Try the wrapper libraries first!

You may first want to consider the following ClojureScript libraries which wrap some functionality from Google Closure Library. Their source code also serves as good examples of how to use Closure directly.

ClojureScript wrapper	Closure Libraries
cljs-time	goog.date
cljs-http	goog.net, goog.uri
cljs-ajax	goog.net, goog.uri, goog.json
cuerdas	goog.string

* included in ClojureScript's core library

Using Google Closure directly

Some helpful blog posts:

• ClojureScript Made Easy - Don't forget about Google Closure
• ClojureScript Made Easy - When do I use :require vs :import?

To use Google Closure in your ClojureScript code, the rule is to use:

• :import for Closure classes (which are also namespaces, like goog.Uri) and enums
• :require for everything else

Import a class

This is only for when you would like to refer directly to a class which is also a namespace, otherwise just use :require in your ns form or use the require REPL helper.

(ns example.core
  (:import goog.Uri))

;; in REPL
(import 'goog.Uri)
(Uri. "http://example.com")
;;=> #<http://example.com>

Import an enum

(ns example.core
  (:import [goog.events EventType]))

;; in REPL
(import '[goog.events EventType])
EventType.CLICK
;;=> "click"

Requiring a function

(ns example.core
  (:require [goog.math :as math]))

;; in REPL
(require '[goog.math :as math])
(math/clamp -1 0 5)
;;=> 0

⚠️	Sometimes symbols are __not auto-included__ when requiring their parent namespace. This happens when those symbols are in their own file and require specific inclusion

(ns example.core
  (:require
    [goog.string :as gstring]
    goog.string.format))

;; in REPL
(require '[goog.string :as gstring])
(require 'goog.string.format)

(goog.string.format "%05d" 123)
;;=> 00123

;; or use the alias
(gstring/format "%05d" 123)
;;=> 00123

Searching for Examples

You can look for cljs files on Github that use goog.dom with the following search:

Search GitHub: "[goog.dom extension:cljs](https://github.com/search?utf8=%E2%9C%93&q=goog.dom+extension%3Acljs&type=Code&ref=searchresults)"

Or you can search Google Closure Library on Github for keywords pertaining to a function it might have:

Search Closure Library on Github: "[hours minutes](https://github.com/google/closure-library/search?utf8=%E2%9C%93&q=hours+minutes)"