Readonly properties in interfaces in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a readonly property in the interface.

Typescript

interface User {
  [1] id: number;
}

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

Aprivate

Bconst

Cstatic

Dreadonly

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'const' inside interfaces is invalid.

Using 'static' or 'private' does not make properties readonly.

The readonly keyword makes the property immutable after initialization.

2fill in blank

medium

Complete the code to create an interface with a readonly property 'name'.

Typescript

interface Person {
  [1] name: string;
}

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

Areadonly

Bprivate

Cpublic

Dstatic

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'private' instead of 'readonly'.

Forgetting to add any modifier.

The readonly keyword ensures the 'name' property cannot be changed after assignment.

3fill in blank

hard

Fix the error in the interface by making the property 'age' readonly.

Typescript

interface Employee {
  [1] age: number;
}

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

Areadonly

Bstatic

Cconst

Dprivate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'const' inside interfaces.

Using 'private' or 'static' incorrectly.

Only readonly is valid to make interface properties immutable.

4fill in blank

hard

Fill both blanks to declare a readonly property 'title' of type string in the interface.

Typescript

interface Book {
  [1] [2]: string;
}

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

Areadonly

Bprivate

Ctitle

Dstatic

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of keyword and property name.

Using 'private' or 'static' instead of 'readonly'.

The property name is 'title' and it must be marked readonly to prevent changes.

5fill in blank

hard

Fill all three blanks to declare a readonly property 'id' of type number in the interface.

Typescript

interface Product {
  [1] [2]: [3];
}

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

Areadonly

Bid

Cnumber

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'string' instead of 'number' for the type.

Omitting the readonly keyword.

The property 'id' is marked readonly and typed as number.