Homepage: https://github.com/mooz/js2-mode
Author: Dmitry Gutov, Steve Yegge, mooz
Updated:
Improved JavaScript editing mode
This JavaScript editing mode supports:
- strict recognition of the Ecma-262 language standard
- support for most Rhino and SpiderMonkey extensions from 1.5 and up
- parsing support for ECMAScript for XML (E4X, ECMA-357)
- accurate syntax highlighting using a recursive-descent parser
- on-the-fly reporting of syntax errors and strict-mode warnings
- undeclared-variable warnings using a configurable externs framework
- "bouncing" line indentation to choose among alternate indentation points
- smart line-wrapping within comments and strings
- code folding:
- show some or all function bodies as {...}
- show some or all block comments as /*...*/
- context-sensitive menu bar and popup menus
- code browsing using the `imenu' package
- many customization options
Installation:
To install it as your major mode for JavaScript editing:
(add-to-list 'auto-mode-alist '("\\.js\\'" . js2-mode))
Alternatively, to install it as a minor mode just for JavaScript linting,
you must add it to the appropriate major-mode hook. Normally this would be:
(add-hook 'js-mode-hook 'js2-minor-mode)
You may also want to hook it in for shell scripts running via node.js:
(add-to-list 'interpreter-mode-alist '("node" . js2-mode))
Use Emacs 27 and want to write JSX? Then use `js2-minor-mode' as described
above. Use Emacs 26 or earlier? Then use `js2-jsx-mode':
(add-to-list 'auto-mode-alist '("\\.jsx?\\'" . js2-jsx-mode))
(add-to-list 'interpreter-mode-alist '("node" . js2-jsx-mode))
Note that linting of JSX code may fail in both modes.
To customize how it works:
M-x customize-group RET js2-mode RET
Notes:
This mode includes a port of Mozilla Rhino's scanner, parser and
symbol table. Ideally it should stay in sync with Rhino, keeping
`js2-mode' current as the EcmaScript language standard evolves.
Unlike cc-engine based language modes, js2-mode's line-indentation is not
customizable. It is a surprising amount of work to support customizable
indentation. The current compromise is that the tab key lets you cycle among
various likely indentation points, similar to the behavior of python-mode.
This mode does not yet work with "multi-mode" modes such as `mmm-mode'
and `mumamo', although it could be made to do so with some effort.
This means that `js2-mode' is currently only useful for editing JavaScript
files, and not for editing JavaScript within