Last Updated: August 19, 2017

Format JSON within VIM with node.js

Put the following snip to your vimrc, whenever you open a JSON file, you can format it with hotkey fj in normal mode.

function FmtJSON(...) 
 let code="\"
 \ var i = process.stdin, d = '';
 \ i.resume();
 \ i.setEncoding('utf8');
 \ i.on('data', function(data) { d += data; });
 \ i.on('end', function() {
 \ try {
 \ JSON.parse(d) 
 \ } catch(e) { return console.log(d); }
 \ console.log(JSON.stringify(JSON.parse(d), null, 
 \ " . (a:0 ? a:1 ? a:1 : 2 : 2) . "));
 \ });\""
 execute "%! node -e " . code 
endfunction
nmap fj :<C-U>call FmtJSON(v:count)<CR>

The main part of function FmtJSON is copied from somewhere, but if the JSON file is malformed you probably override the original file unexpectedly, so I added try-catch in the end event handler.

#vim

#json

#node