使用 for...in 语句遍历 object 的键

Question

Given this object and for...in statement, my expected output of countOnline is false . We are iterating and the online key for other object entries has been changed to the value 33. Why are we getting true back when we have a strict equality check for boolean?

let users = {
  Alan: {
    age: 27,
    online: true
  },
  Jeff: {
    age: 32,
    online: 33
  },
  Sarah: {
    age: 48,
    online: 33
  },
  Ryan: {
    age: 19,
    online: 33
  }
};

function countOnline(usersObj) {

  for (let user in users) {
    if (users[user].online === true) {
      return true;
    } else {
      return false;
    }
  }
}

console.log(countOnline(users));

Answer 1

The first element in your array has online: true , and your function returns when it finds a user with online: true ... so it just stops the loop and returns with true on the first iteration:)