Check if an Object has a Property (solution ffc is not good)

JavaScript
1

Tell us what’s happening:

the solution proposed by the freecodecamp is not good for this exercise.

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

function isEveryoneHere(obj) {
  // change code below this line
  if(users.hasOwnProperty('Alan','Jeff','Sarah','Ryan')) {
    return true;
  }
  return false;
  // change code above this line
}

console.log(isEveryoneHere(users));

because once the function to return true is over

even if there is a name that does not exist

Your code so far


let users = {
    Alan: {
      age: 27,
      online: true
    },
    Jeff: {
      age: 32,
      online: true
    },
    Sarah: {
      age: 48,
      online: true
    },
    Ryan: {
      age: 19,
      online: true
    }
  };
  
  function isEveryoneHere(obj) {
    // change code below this line
      let arr = ["Alan","Jeff","Sarah","Ryan"];
      var counter = 0;
      for(var i = 0; i<arr.length;i++){
        if(!obj.hasOwnProperty(arr[i])){
          counter++;
        }
        
      }

      if(counter != 0){
          return false;
      }
      else{
          return true;
      }
    // change code above this line
  }
  
  console.log(isEveryoneHere(users));

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-data-structures/check-if-an-object-has-a-property

2

Yes, the solution given is just completely wrong. The reason you’re seeing that behaviour is because hasOwnProperty only takes a single argument and ignores the rest (users.hasOwnProperty('Alan', 'snrub', 'xtwysk', 'foobar', 'qkqsub') returns true for example).

Place to report issues is on GitHub — you can report an issue, here’s the overview of what to do if you’ve found an issue https://github.com/freeCodeCamp/freeCodeCamp/blob/master/README.md#found-a-bug