json stringify recursive

var test = {  name: “John”,  age: 21,  scores: [89, 72, 96, 55, 66]}function type(obj) {  return Object.prototype.toString.call(obj).match(/.* (.*)\]/)[  1]}function stringify(obj) {  if (type(obj) === “Function”) {    return null  }  if (type(obj) === “Undefined”) {    return null  }  if (type(obj) === “Null”) {    return “null”  }  if (type(obj) === “Number”) {    return obj  }  if (type(obj) === “String”) {    return ‘”’ + obj + ‘”’  }  if (type(obj) === “Array”) {    return ‘[‘ +      obj.map(function(o) {        return stringify(o)      }).join(“,”)      + ‘]’  }  if (type(obj) === “Object”) {    var result = []    Object.keys(obj).forEach(function(key) {      var val = stringify(obj[key])      if (val !== null) {        result.push(‘”’ + key + ‘”: ‘ + val)      }    })    return “{“ + result.join(“,”) + “}”  }}stringify(test) //==> {“name”: “John”,”age”: 21,”scores”: [89,72,96,55,66]}