pretty-print JSON using JavaScript
Pretty-printing is implemented natively in JSON.stringify(). The third argument enables pretty printing and sets the spacing to use:
var str = JSON.stringify(obj, null, 2); // spacing level = 2If you need syntax highlighting, you might use some regex magic like so:
function syntaxHighlight(json) { if (typeof json != 'string') { json = JSON.stringify(json, undefined, 2); } json = json.replace(/&/g, '&').replace(/</g, '<').replace(/>/g, '>'); return json.replace(/("(\\u[a-zA-Z0-9]{4}|\\[^u]|[^\\"])*"(\s*:)?|\b(true|false|null)\b|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)/g, function (match) { var cls = 'number'; if (/^"/.test(match)) { if (/:$/.test(match)) { cls = 'key'; } else { cls = 'string'; } } else if (/true|false/.test(match)) { cls = 'boolean'; } else if (/null/.test(match)) { cls = 'null'; } return '<span class="' + cls + '">' + match + '</span>'; });}See in action here: jsfiddle
Or a full snippet provided below:
User Pumbaa80's answer is great if you have an object you want pretty printed. If you're starting from a valid JSON string that you want to pretty printed, you need to convert it to an object first:
var jsonString = '{"some":"json"}';var jsonPretty = JSON.stringify(JSON.parse(jsonString),null,2); This builds a JSON object from the string, and then converts it back to a string using JSON stringify's pretty print.