About 
Improved JavaScript editing mode for GNU Emacs (description here).
For some of the latest changes, see latest user-visible changes.
Installation
The stable versions are hosted at GNU ELPA
(M-x list-packages).
You can also install the latest development version from
MELPA.
Requirements
Emacs 24.1+ and cl-lib (either built-in or installed from GNU ELPA).
React and JSX
The currently recommended solution is to install Emacs 27 (still in
development, you can build from
source
or e.g. install a snapshot from a
PPA) and
use js-mode as the major mode. To make use of the JS2 AST and the
packages that integrate with it, we recommend js2-minor-mode. See
the corresponding instructions in the
Commentary.
js-mode in Emacs 27 includes full support for syntax highlighting
and indenting of JSX syntax.
rjsx-mode is an
alternative option which comes with certain tradeoffs.
Bugs
-
See broken syntax highlighting and timer errors? Recently upgraded
Emacs from version 24.2 or earlier? Try
reinstalling or byte-recompiling
the package. -
Any indentation problems should be reported with
M-x report-emacs-bug
(please try reproducing them withjs-modefirst, for clarity).
Starting with Emacs 25,js2-modedelegates indentation to
the indentation engine ofjs-mode.
Please report other problems at http://github.com/mooz/js2-mode/issues.
Contributing
js2-mode is subject to the same
copyright assignment
policy as Emacs itself, org-mode, CEDET and other packages in
GNU ELPA.
Any
legally significant
contributions can only be accepted after the author has completed their
paperwork. Please ask for the request form, and we'll send it to you.
See Also
Some third-party modes that use the generated syntax tree: