Declaration merging for namespaces in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a namespace named 'Shapes'.

Typescript

namespace [1] {
  export const pi = 3.14;
}

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AShapes

BMath

CCircle

DGeometry

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different namespace name than 'Shapes'.

The namespace is named 'Shapes' to group related constants and types.

2fill in blank

medium

Complete the code to add a function 'area' inside the 'Shapes' namespace.

Typescript

namespace Shapes {
  export function [1](radius: number): number {
    return pi * radius * radius;
  }
}

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Aperimeter

Bcircumference

Cdiameter

Darea

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name unrelated to area calculation.

The function calculates the area of a circle, so it should be named 'area'.

3fill in blank

hard

Fix the error in the code by completing the namespace merging correctly.

Typescript

namespace Shapes {
  export const color = 'red';
}

namespace [1] {
  export function getColor() {
    return color;
  }
}

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ACircle

BShapes

CGeometry

DColors

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different namespace name prevents merging.

To merge declarations, the second namespace must have the same name 'Shapes'.

4fill in blank

hard

Fill both blanks to complete the merged namespace with a variable and a function accessing it.

Typescript

namespace Shapes {
  export let [1] = 'blue';
}

namespace Shapes {
  export function get[2]() {
    return [1];
  }
}

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Acolor

BColor

Cshape

DShape

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching variable and function names.

The variable is 'color' and the function is 'getColor' to access it.

5fill in blank

hard

Fill all three blanks to create a merged namespace with a type, a variable, and a function returning the variable.

Typescript

namespace Shapes {
  export type [1] = { radius: number };
  export let [2]: [1] = { radius: 5 };
  export function getRadius() {
    return [3].radius;
  }
}

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ACircle

Bcircle

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent capitalization between type and variable.

The type is 'Circle' (capitalized), the variable is 'circle' (lowercase), and the function returns circle.radius.