What survives compilation to JavaScript in Typescript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable that will appear in the compiled JavaScript.

Typescript

let [1] = 5;

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

Anumber

Bcount

Ctype

Dinterface

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a TypeScript type or interface name instead of a variable name.

The variable name count will appear in the compiled JavaScript. Types like number, type, and interface are removed during compilation.

2fill in blank

medium

Complete the code to declare a function that will be present in the compiled JavaScript.

Typescript

function [1]() { return 10; }

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Acalculate

BMyType

CNumber

DIResult

Attempts:

3 left

💡 Hint

Common Mistakes

Using type or interface names as function names.

The function name calculate will appear in the compiled JavaScript. Types and interfaces like MyType, Number, and IResult are removed.

3fill in blank

hard

Fix the error in the code so that the variable survives compilation.

Typescript

const [1]: string = "hello";

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Atype

Bstring

Cgreeting

Dinterface

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a type or interface keyword as variable name.

The variable greeting will be present in the compiled JavaScript. The type annotation : string is removed, but the variable name remains.

4fill in blank

hard

Fill both blanks to create a class and method that survive compilation.

Typescript

class [1] {
  [2]() { return 42; }
}

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

ACalculator

Bcompute

CIResult

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using type or interface names as class or method names.

The class Calculator and its method compute will appear in the compiled JavaScript. Types like IResult and number do not survive.

5fill in blank

hard

Fill all three blanks to create an object with a property and a method that survive compilation.

Typescript

const obj = {
  [1]: 10,
  [2]() { return this.[3]; }
};

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

Avalue

BgetValue

Dtype

Attempts:

3 left

💡 Hint

Common Mistakes

Using type names as property or method names.

The property value and method getValue survive compilation. The method returns the property value. The type type does not survive.