这个递归函数有什么问题

Question

我正在尝试使用递归计算对象中的字符串数，包括嵌套对象和数组中的字符串。 为什么我得到 3 而不是 7;

function strCount(obj, count = 0){
  for (var key in obj) {
    if (typeof obj[key] === 'object') {
      strCount(obj[key], count);
    } else if (typeof obj[key] === 'string') {
      count++;
    }
  }
  return count;
}
var myobj = {
  first:  "1",
  second: "2",
  5: 'sd',
  third:  false,
  fourth: ["anytime",2,3,4],
  fifth:  null,
  sixth:  undefined,
  seventh:{ ana: 'hell', did: 5, boo : 'foo', har : ['kill', 5]}
};
alert(strCount(myobj));

Answer 1

不要忘记将

递归调用的结果添加到count：

function strCount(obj) {
  var count = 0;
  for (var key in obj) {
    if (typeof obj[key] === 'object') {
      count += strCount(obj[key]);
    } else if (typeof obj[key] === 'string') {
      count++;
    }
  }
  return count;
}
var myobj = {first:"1",second:"2",5:'sd',third:false,fourth:["anytime",2,3,4],fifth:null,sixth:undefined,seventh:{ana:'hell',did:5,boo:'foo',har:['kill',5]}};
alert(strCount(myobj));

Answer 2

您应该将第 4 行更改为 count = strCount(obj[key], count); 。

function strCount(obj, count = 0) {
  for (var key in obj) {
    if (typeof obj[key] === 'object') {
      count = strCount(obj[key], count);
    } else if (typeof obj[key] === 'string') {
      count++;
    }
  }
  return count;
}
var myobj = {
  first: "1",
  second: "2",
  5: 'sd',
  third: false,
  fourth: ["anytime", 2, 3, 4],
  fifth: null,
  sixth: undefined,
  seventh: {
    ana: 'hell',
    did: 5,
    boo: 'foo',
    har: ['kill', 5]
  }
};
alert(strCount(myobj));