Object.create usage in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does Object.create() do in JavaScript?

Object.create() creates a new object with the specified prototype object and properties. It lets you set the prototype of the new object directly.

beginner

How do you create an object with Object.create() that inherits from another object?

<p>Pass the object you want to inherit from as the first argument to <code>Object.create()</code>. For example: <code>const child = Object.create(parent);</code></p>

intermediate

What is the difference between Object.create(null) and {}?

Object.create(null) creates an object with no prototype, so it doesn't inherit any properties like toString. {} creates an object that inherits from Object.prototype.

intermediate

Can you add properties when creating an object with Object.create()?

Yes, the second argument of Object.create() lets you define properties with descriptors. For example: Object.create(proto, { prop: { value: 42, writable: true, enumerable: true, configurable: true } }).

intermediate

Why might you use Object.create() instead of a constructor function?

It gives you direct control over the prototype chain without needing to define a constructor. This can be simpler for creating objects that inherit from others without extra setup.

What is the first argument to Object.create()?

A A constructor function

B An array of property names

C The prototype object for the new object

D A string representing the object type

The first argument sets the prototype of the new object created by Object.create().

What does Object.create(null) create?

A An object with no prototype

B An empty array

C An object with default properties

D A function object

Object.create(null) creates an object that does not inherit from Object.prototype.

How can you add properties when using Object.create()?

A By calling <code>addProperty()</code> method

B By passing a second argument with property descriptors

C By passing an array of values as the second argument

D You cannot add properties during creation

The second argument to Object.create() is an object defining property descriptors.

Which of these is true about objects created with Object.create()?

A They inherit from the object passed as the first argument

B They always have <code>Object.prototype</code> as prototype

C They cannot have methods

D They are frozen by default

The new object inherits from the prototype object passed as the first argument.

Why use Object.create() instead of a constructor function?

A Because it automatically adds methods

B Because it runs faster

C Because it creates arrays

D To directly set the prototype without defining a constructor

Object.create() lets you create an object with a specific prototype without needing a constructor function.

Explain how Object.create() works and how it is used to set an object's prototype.

Think about how inheritance works in JavaScript objects.

Describe the difference between an object created with Object.create(null) and a normal object literal {}.

Consider what properties and methods are available on each.