Instance methods in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an instance method named greet inside the class.

Javascript

class Person {
  greet() {
    return [1];
  }
}

const p = new Person();
console.log(p.greet());

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

A'Hello! I am an instance method.'

BHello

Cgreet

Dfunction greet()

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to return a string value.

Using function keyword inside class method.

The instance method greet returns the string 'Hello! I am an instance method.'. The method body must return a string value.

2fill in blank

medium

Complete the code to call the instance method greet on the object p.

Javascript

class Person {
  greet() {
    return 'Hi!';
  }
}

const p = new Person();
console.log(p.[1]());

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

Athis

BPerson

Cnew

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Calling the class name instead of the method.

Forgetting the parentheses when calling the method.

To call the instance method greet on the object p, use p.greet().

3fill in blank

hard

Fix the error in the instance method to correctly access the name property.

Javascript

class Person {
  constructor(name) {
    this.name = name;
  }
  greet() {
    return 'Hello, ' + [1] + '!';
  }
}

const p = new Person('Alice');
console.log(p.greet());

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

Aself.name

Bname

Cthis.name

DPerson.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using the property name without 'this'.

Using class name to access instance properties.

Inside instance methods, use 'this' to access instance properties like name.

4fill in blank

hard

Fill both blanks to create an instance method that returns the person's full name.

Javascript

class Person {
  constructor(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
  fullName() {
    return [1] + ' ' + [2];
  }
}

const p = new Person('John', 'Doe');
console.log(p.fullName());

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

Athis.firstName

BfirstName

Cthis.lastName

DlastName

Attempts:

3 left

💡 Hint

Common Mistakes

Using property names without 'this'.

Forgetting to add space between names.

Use 'this.firstName' and 'this.lastName' to access the instance properties inside the method.

5fill in blank

hard

Fill all three blanks to create an instance method that updates the person's age and returns a message.

Javascript

class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }
  haveBirthday() {
    this.age = this.age [1] 1;
    return `$[2] is now $[3] years old.`;
  }
}

const p = new Person('Emma', 29);
console.log(p.haveBirthday());

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

A+

Bthis.name

Cthis.age

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of '+' to increment age.

Not using 'this' to access properties.

Incorrect template literal syntax.

The method increments age by 1 using '+', then returns a message using this.name and this.age.