gistfile1.txt

function tokenize(json) {
  var regex = /(true|false|null|".*?[^\\]"|\d+|\[|\]|{|})/g
  return json.match(regex);
}

function cast(data) {
  if (typeof data === 'string') {
    if (data.match(/".*?[^\\]"/))  { return data.slice(1, -1).replace(/\\/g, ""); }
    if (data.match(/\d+/)) { return Number(data); }
    if (data === 'true' || data == 'false') { return data === 'true'; }
    if (data === 'null') { return null; }
  }
  return data;
}

function parse(json) {
  var tokens = tokenize(json);
  var stack = [];
  
  tokens.forEach(function(token) {
    if (token === ']') {
      var parsedArray = []; 
      var latest = stack.pop();
      while (latest !== '[') {
        parsedArray.unshift(cast(latest));
        latest = stack.pop();
      } 
      stack.push(parsedArray);
    } else if (token === '}') {
      var parsedObject = {};
      var value = stack.pop();
      while (value !== '{') {
        var key = stack.pop();
        parsedObject[cast(key)] = cast(value);
        value = stack.pop(); 
      } 
      stack.push(parsedObject);
    } else {
      stack.push(token);
    }
  });   

  return cast(stack[0]);
}

//var string = JSON.stringify({x: [1,2,"3",[4,5, {a: 1},"hi", 6324], 'hello "fi"', [], [5], [1,[2,"3"]], "3"], y: 2});
var string = JSON.stringify('false "hi"');
console.log(string);
console.log(parse(string) == JSON.parse(string))
console.log(parse(string))
console.log(JSON.parse(string))