ac-js2

An attempt at context sensitive auto-completion for Javascript in Emacs using js2-mode's parser and Skewer-mode (requires Emacs 24.3). Inspired by the work of others on projects such as js2-mode, skewer-mode and js2-refactor I decided to add to the concept of Emacs as a Javascript IDE.

Here is a screenshot of the auto completion in action using the optional dependency, auto-complete-mode.

Features

• Auto complete with js2-browser-externs
• Auto complete with js2-keywords
• Auto complete with js2-ecma-262-externs

Each of the above settings can be customized and are enabled by default.

• Partial support for completing properties
• Show function interface or initial value for object properties
• Support for external libraries

Ac-js2 uses skewer-mode to evaluate Javascript code in the browser which could have undesired side effects. Therefore these features are turned off by default, see Setup to enable these features anyway :).

• Navigation commands to jump to variables, functions and object properties.

i.e. Given the following proprety reference:

foo.bar.baz();

placing the cursor on foo, bar or baz and executing ac-js2-jump-to-definition or M-. will take you straight to their respective definitions. Executing M-, will jump you back to where you were.

• Completion of variable and function names in current scope
• Popup documentation for variables and function names in buffer

Experimental yansippet integration

Recently added ac-js2-expand-function that will expand a function's parameters bound to C-c C-c. Expansion will only work if the cursor is after the function.

Note: Navigation only works if the definition is in the same file.

Installation

Easiest way to get ac-js2 is to install it from MELPA. You may need this snippet

(add-to-list 'package-archives
              '("melpa" . "http://melpa.milkbox.net/packages/") t)

if you don't have it already to fetch packages from MELPA.

Set up ac-js2 for auto-complete like this:

(add-hook 'js2-mode-hook 'ac-js2-mode)

Set up ac-js2 for company like this:

(add-to-list 'company-backends 'ac-js2-company)

Dependencies

• skewer-mode (MELPA)
• js2-mode (ELPA/MELPA)

Optional, depending on which completion framework you want to use:

• auto-complete (ELPA/MELPA)
• company (ELPA/MELPA)

Setup

Copy the snippet below if you want to evaluate your Javascript code for candidates. Not setting this value will still provide you with basic completion.

(setq ac-js2-evaluate-calls t)

Add any external Javascript files to the variable below. Make sure you have initialised ac-js2-evaluate-calls to t if you add any libraries.

(setq ac-js2-external-libraries '("full/path/to/a-library.js"))

Usage

Call run-skewer and open up a Javascript file. Type part of a variable and call completion-at-point or if you have auto-complete installed wait for the popup.

Note that any code you evaluate using Skewer may add completion candidates for the global object.