A simple pure python Mercurial precommit hook script to fix trailing commas in JSON files and to make sure that json can load up the file. It's not a JSON Lint run but generally good enough to find issues.
There's lots of other options out there, for example: JSHint but this hook doesn't require Node or anything outside of Python.
Clone this repo: git clone git://github.com/leos/hg-json-hook.git
Add the hook to your hgrc:
[hooks]
precommit = python:/home/leo/hg-json-hook/hgjsonhook.py:run
Replace /home/leo/ with wherever you cloned it to.
The hook hasn't been tested as anything other than a precommit. Pull requests welcome if it works as a different type of hook.
The hook will automatically run on commit. If there are any trailing commas detected in json files that are part of the commit, you'll be prompted to fix them. Hit y to correct them or n to ignore.
If the json.loads fails, you'll be given the message from that. Newer simplejson versions tend to be more descriptive.
Python 2.4+
Uses simplejson if it's installed (required on Python 2.4, 2.5)
ANSI compatible terminal for color (Windows users need ansi.sys or equivalent - try ansicon)