Quiz

JavaScript Objects Quiz

8 questions about working with objects: properties, methods, destructuring, and nested structures.

questions

~4 min

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instant result

Question 1 of 8

How do you access the name property of the user object?

user->name✓✗ user.name✓✗ user::name✓✗ user(name)✓✗

Question 2 of 8

How do you add a new property to an existing object?

user.new = "value"✓✗ user.city = "Kyiv"✓✗ user += city✓✗ You can't add a property after an object is created✓✗

Question 3 of 8

How do you delete a property from an object?

user.remove(property)✓✗ delete user.property✓✗ user.property = null is the only way✓✗ user.pop(property)✓✗

Question 4 of 8

What does Object.keys(user) do?

Returns the property values✓✗ Returns an array with the names of all the object's properties✓✗ Deletes all properties✓✗ Copies the object✓✗

Question 5 of 8

How do you check if an object has a specific property?

user.has("name")✓✗ "name" in user✓✗ user.contains("name")✓✗ It's not possible to check✓✗

Question 6 of 8

What does the spread operator do when copying an object: const copy = {...user}?

Creates a reference to the same object✓✗ Creates a shallow copy of the object✓✗ Does nothing✓✗ Throws an error✓✗

Question 7 of 8

How do you access a property whose name is stored in a variable called key?

user.key✓✗ user[key]✓✗ user(key)✓✗ It's not possible✓✗

Question 8 of 8

What does typeof {} return?

"object"✓✗ "array"✓✗ "function"✓✗ "undefined"✓✗

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