Better JSON for VIM

Distinct highlighting of keywords vs values, JSON-specific (non-JS) warnings. Customization of Jeroen Ruigrok van der Werven's vim-json highlighting script with Rogerz Zhang's indent script. Pathogen-friendly. Vundle-friendly too.

Specific customizations

• Added distinct highlighting for keywords vs values! (This is what made me start this plugin.)
• Added folding of {...} and [...] blocks. To enable it :setlocal foldmethod=syntax (do it permanently on the ftplugin/json.vim file).
• JSON-specific warnings (red highlights):
  • Warn about no-quotes in keywords and single-quotes in keywords and values.
  • Warn about decimals smaller than 1 that don't start with a 0 (.1 gives a warning, it should be 0.1).
  • Warn about comments // and trailing semicolons ;.
  • Warn about missing commas between elements of an object and elsewhere.
  • Warn about trailing commas after the last element in arrays or objects.
  • (All warnings can be turned off with a let g:vim_json_warnings=0 in your vimrc.)
• Recognize .jsonp file type. In JSONP, the wrapping function call at the beginning and the closing semicolon are recognized.

Why use separate JSON highlighting instead of just Javascript?

Here's 2 compelling reasons:

1. All JSON is Javascript but NOT all Javascript is JSON. So {property:1} is invalid because property does not have double quotes around it. {'property':1} is also invalid, because it's single quoted while the only thing that can placate the JSON specification is double quoting. JSON is even fussy enough that {"property":.1} is invalid too, because you should have of course written {"property":0.1}. Also, don't even think about having comments or semicolons, you guessed it: they're invalid. The point being that your syntax highlighter should warn you about these errors, in realtime, which is something that the Javascript highlighter doesn't (because in Javacript they're not errors!).

2. Distinct highlighting for keywords. JSON is an extremely lightweight data format but at its core lies an inescapable conceptual distinction: there are keywords and there are values. There's nothing much to the format besides that, so we might as well display keywords and values differently. This is something that gets lost with Javascript-inspired syntax highlighters, which see keywords as just another string since JSON requires them double quoted. So JSON files remain an impenetrable, indistinct wall of text.

Other recommended software

elzr's vim-json: Optionally adds JSON concealing as a feature JSON Formatter: Chrome extension for printing JSON and JSONP nicely when you visit it 'directly' in a browser tab.