Format JSON in VIM

Put vim snippet(which depends on python) below in your vim configuration file

if has("python")
    python << EOF
import vim
import json
def FormatJSON(fmtlStart, fmtlEnd):
    fmtlStart = fmtlStart-1
    jsonStr = "\n".join(vim.current.buffer[fmtlStart:fmtlEnd])
    prettyJson = json.dumps(json.loads(jsonStr), sort_keys=True, indent=4, separators=(',', ': '), ensure_ascii=False)
    prettyJson = prettyJson.encode('utf8')
    vim.current.buffer[fmtlStart:fmtlEnd] = prettyJson.split('\n')
EOF

    com! -range -bar FmtJSON :python FormatJSON(<line1>, <line2>)
endif

Now, open a file containing json string, go to the line where the json string starts.

If the json string is all in one line like below, just run command :FmtJSON:

{"name": "brook", "country": "中国"}

If the json string is across multiple lines like below, press V to enter visual mode first, then select the json string from start to end, then run command :FmtJSON:

{"name": "brook",
    "country": "中国"}