Object.create usage in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new object with the specified prototype.

Javascript

const proto = { greet() { return 'Hello'; } };
const obj = Object.[1](proto);
console.log(obj.greet());

Drag options to blanks, or click blank then click option'

Aassign

BdefineProperty

Ccreate

DsetPrototypeOf

Attempts:

3 left

💡 Hint

Common Mistakes

Using Object.assign instead of Object.create.

Trying to use Object.setPrototypeOf to create an object.

Using Object.defineProperty which is for properties, not creating objects.

The Object.create method creates a new object with the given prototype object.

2fill in blank

medium

Complete the code to add a property to the new object created with Object.create.

Javascript

const proto = { type: 'animal' };
const obj = Object.create(proto);
obj.[1] = 'dog';
console.log(obj.type, obj.name);

Drag options to blanks, or click blank then click option'

Atype

Bname

Cspecies

Dbreed

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to overwrite the prototype property 'type'.

Adding a property that already exists on the prototype.

Confusing prototype properties with own properties.

The property name is added directly to the new object, while type comes from the prototype.

3fill in blank

hard

Fix the error in the code to properly create an object with a prototype and a property descriptor.

Javascript

const proto = { speak() { return 'Hi'; } };
const obj = Object.create(proto, {
  age: { [1]: 5, writable: true }
});
console.log(obj.age, obj.speak());

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Avalue

Bconfigurable

Cenumerable

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'get' instead of 'value' in the descriptor.

Omitting the 'value' key causing undefined property.

Confusing writable with value.

The property descriptor must use value to set the property's value.

4fill in blank

hard

Fill both blanks to create an object with a prototype and add a method that returns a greeting.

Javascript

const proto = {
  [1]() {
    return 'Hello, ' + this.name;
  }
};
const obj = Object.create(proto);
obj.name = 'Alice';
console.log(obj.[2]());

Drag options to blanks, or click blank then click option'

Agreet

BsayHello

Chello

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using different method names in definition and call.

Choosing method names that are not consistent.

Forgetting to define the method on the prototype.

The method name must be the same when defined and called. Here, 'greet' is used consistently.

5fill in blank

hard

Fill all three blanks to create an object with a prototype, add a property with descriptor, and call a method.

Javascript

const proto = {
  [1]() {
    return `Age is ${this.age}`;
  }
};
const obj = Object.create(proto, {
  age: { [2]: 30, writable: true, enumerable: true }
});
console.log(obj.[3]());

Drag options to blanks, or click blank then click option'

AgetAge

Bvalue

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using different method names in definition and call.

Using incorrect keys in property descriptor.

Forgetting to make the property enumerable.

The method is named 'getAge' and is called as such. The property descriptor uses 'value' to set the age.