---
title: Check if an Object has a Property
---
# Check if an Object has a Property


---
## Solutions

<details><summary>Solution 1 (Click to Show/Hide)</summary>

```javascript
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) {
  if (
    obj.hasOwnProperty("Alan") &&
    obj.hasOwnProperty("Jeff") &&
    obj.hasOwnProperty("Sarah") &&
    obj.hasOwnProperty("Ryan")
  ) {
    return true;
  }
  return false;
}
```

#### Code Explanation

* Checks whether object contains all users by using the `hasOwnProperty` method for each name with the `&&` operator to return a `true` or `false` value.
</details>

<details><summary>Solution 2 (Click to Show/Hide)</summary>

```javascript
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) {
  return ["Alan", "Jeff", "Sarah", "Ryan"].every(name =>
    obj.hasOwnProperty(name)
  );
}
```

#### Code Explanation

* Uses an array with all of the names which should be present in the object.
* The `every` method is used to validate all of names used in conjunction with the `hasOwnProperty` method result in a value of `true` being returned during each iteration.
* If at least one name is not found using the `hasOwnProperty` method, the `every` method returns `false`.

#### Relevant Links

* [Array.prototype.every](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every)

</details>