js深いコピー

 function clone(data) {
      if (typeof data === 'object') {
        var newData = Array.isArray(data) ? [] : {};
        for (var i in data) {
          newData[i] = clone(data[i])
        }
        return newData;
      } else {
        return data;
      }
    }
    var a = {a: 1, b: 2, c: {d: 1}};
    var b = clone(a)
    console.log(b)
    b.c.d = 3
    console.log(a,b)

function cloneTwo(data) {
     var newData = JSON.stringify(data);
     return JSON.parse(newData);
    }
    var aa = {a: 1, b: 2, c: {d: 1}};
    var bb = cloneTwo(aa)
    console.log(bb)
    bb.c.d = 3
    console.log(aa,bb)