Constructors in classes in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a constructor in the class.

Javascript

class Person {
  constructor([1]) {
    this.name = name;
  }
}

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

Aname

Bage

Cthis

Dconstructor

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this' as a parameter name.

Using 'constructor' as a parameter name.

Using a parameter unrelated to the property.

The constructor needs a parameter name to assign it to the object.

2fill in blank

medium

Complete the code to create a new instance of the class.

Javascript

const person1 = new Person([1]);

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

APerson

Bthis

Cconstructor

D'John'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the class name instead of a string.

Passing 'constructor' or 'this' instead of a string.

Not passing any argument.

To create a new object, pass the name string to the constructor.

3fill in blank

hard

Fix the error in the constructor parameter to correctly assign the property.

Javascript

class Animal {
  constructor([1]) {
    this.type = type;
  }
}

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

Athis.type

Btype

CanimalType

Dtype()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'this.type' as a parameter.

Using a function call 'type()' as a parameter.

Using a different parameter name without updating the assignment.

The constructor parameter should be type to assign it to this.type.

4fill in blank

hard

Fill both blanks to create a class with a constructor that sets two properties.

Javascript

class Car {
  constructor([1], [2]) {
    this.make = make;
    this.year = year;
  }
}

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

Amake

Bmodel

Cyear

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using parameters that do not match the property names.

Using unrelated parameter names like 'model' or 'color'.

The constructor needs parameters make and year to assign to the object properties.

5fill in blank

hard

Fill all three blanks to create a class with a constructor and a method that returns a description.

Javascript

class Book {
  constructor([1], [2]) {
    this.title = title;
    this.author = author;
  }

  getDescription() {
    return `$[3] by ${this.author}`;
  }
}

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

Atitle

Bauthor

Cthis.title

Dtitle()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'title()' instead of 'this.title' in the method.

Using wrong parameter names in the constructor.

Not using 'this' to access object properties.

The constructor parameters are title and author. The method uses this.title to return the description.