在循环javascript中查找最后一次迭代

Question

我有以下示例代码

   var obj = { a: {b:1, c:3 }, d :{f:5}}
        var string = "";
        for(var key in obj){
            for(var subkey in obj[key]){
             string += subkey + "="+ obj[key][subkey] + "&";
             //for last iteration "&" should not be added.
         }
    }
   console.log(string);

输出是

b=1&c=3&f=5& 

要求的输出

b=1&c=3&f=5

Answer 1

另一种方法是:

var obj = { a: {b:1, c:3 }, d :{f:5}},
  array = [];
for(var key in obj){
  for(var subkey in obj[key]){
    array.push(subkey + "="+ obj[key][subkey]);
  }
}
console.log(array.join('&'));