Typescript Quiz Preparation Part 5

Welcome to your Typescript Quiz Preparation Part 5

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How do you define a function average that calculates the average of numbers passed as rest parameters in TypeScript?

function average(...nums: number[]): number { return nums.reduce((total, num) => total + num, 0) / nums.length; }

function average(...nums: number): number { return nums.reduce((total, num) => total + num, 0) / nums.length; }

function average(nums: number[]): number { return nums.reduce((total, num) => total + num, 0) / nums.length; }

function average(nums: number[]): void { return nums.reduce((total, num) => total + num, 0) / nums.length; }

What is the output of the following function call?

function concatenate(...args: string[]): string {
return args.join('');
}

let result = concatenate('Hello', 'World', '!');
console.log(result);

"Hello World!"

"Hello,World!"

"HelloWorld!"

Compilation Error

How do you define a function createPerson that takes parameters name (string) and age (number, default value 18) and returns an object with these properties in TypeScript?

function createPerson(name: string, age: number = 18): { name: string, age: number } { return { name, age }; }

function createPerson(name: string, age: number = 18): { name: string, age: number } = { return { name, age }; }

function createPerson(name: string, age: number): { name: string, age: number } = { return { name, age }; }

function createPerson(name: string, age: number = 18): { name: string, age: number } = { name, age };

How do you define a function sum that accepts any number of arguments of type number and returns their total in TypeScript using rest parameters?

function sum(...args: number[]): number { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number): number { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number[]): void { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number[]): string { return args.reduce((total, num) => total + num, 0); }

How do you call an asynchronous function getData using async/await in TypeScript?

let result = await getData();

let result = getData.async();

let result = await getData.async();

let result = getData();

How do you define a function sum that accepts any number of arguments of type number and returns their total in TypeScript?

function sum(...args: number[]): number { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number): number { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number[]): void { return args.reduce((total, num) => total + num, 0); }

function sum(...args: number[]): string { return args.reduce((total, num) => total + num, 0); }

What is the result of calling the function greet with no arguments?

"Hello, Guest!"

"Hello, undefined!"

"Hello,!"

Compilation Error

Which of the following correctly declares a tuple with a string and a number?

let tuple: [string, number];

let tuple: (string, number);

let tuple: Array;

let tuple: { string, number };

What is the result of calling the function calculateDiscount with arguments 100 and 0.2?

0.02

20

20.0

Compilation Error

How do you declare a function multiply that takes two parameters a (number) and b (number) and returns their product in TypeScript?

function multiply(a: number, b: number): number { return a * b; }

let multiply = (a: number, b: number): number => a * b;

let multiply(a: number, b: number): number => { return a * b; }

let multiply(a, b): number => a * b;

How do you initialize an array of strings with values 'a', 'b', and 'c' in TypeScript?

let letters: string[] = ['a', 'b', 'c'];

let letters: Array = ['a', 'b', 'c'];

let letters: string[] = 'a', 'b', 'c';

Both a) and b)

How do you access the second element of an array items in TypeScript?

items[1];

items[2];

items.get(1);

items.get(2);

How do you declare an array of numbers in TypeScript?

let numbers: number[];

let numbers: Array;

let numbers: [number];

Both a) and b)

How do you call a function printNames that accepts a rest parameter names of type string[] in TypeScript?

printNames(names[]);

printNames(...names);

printNames(names: string[]);

printNames(...names: string[]);

What is the output of the following function call?

function greet(message = 'Hello, World!'): string {
return message;
}

let msg = greet();
console.log(msg);

"Hello,!"

"Hello, undefined!"

Compilation Error

"Hello, Guest!"

How do you call a function printMessage that optionally accepts a parameter message of type string in TypeScript?

printMessage();

printMessage(message: string);

printMessage(message?: string);

printMessage(message: string = '');

How do you define a function calculateArea that optionally takes parameters width (number) and height (number) and returns their product in TypeScript?

function calculateArea(width: number, height: number = 1): number { return width * height; }

function calculateArea(width = 1, height = 1): number { return width * height; }

function calculateArea(width?: number, height?: number): number { return width * height; }

function calculateArea(width: number, height: number?): number { return width * height; }

What does the async keyword do in TypeScript?

It declares a function that returns a Promise

It declares a function that runs asynchronously

It declares a function that accepts async parameters

It declares a function that handles exceptions asynchronously

How do you append a value to an array list in TypeScript?

list.add(value);

list.push(value);

list.append(value);

list.insert(value);

What is the output of the following function call?

function greet(message = 'Hello, World!'): string {
return message;
}

let msg = greet();
console.log(msg);

"Hello, World!"

"Hello,!"

Compilation Error

"World!"

How do you define an asynchronous function fetchData that returns a Promise of type string in TypeScript?

async function fetchData(): Promise { }

function async fetchData(): string { }

async function fetchData(): string { }

function async fetchData(): Promise { }

How do you define a function calculateDiscount that takes parameters price (number) and discount (number, default value 0.1) and returns the discounted price in TypeScript?

function calculateDiscount(price: number, discount: number = 0.1): number { return price * discount; }

function calculateDiscount(price: number = 0.1, discount: number): number { return price * discount; }

function calculateDiscount(price = 1, discount = 0.1): number { return price * discount; }

function calculateDiscount(price: number, discount: number): number { return price * discount; }

What does the following async function fetchData return?

async function fetchData(): Promise {
return 'Data fetched successfully';
}

Promise

'Data fetched successfully'

string

Compilation Error

What is the result of calling the function sum with arguments 1, 2, 3, 4?

10

24

1

Compilation Error

How do you call a function calculate that accepts two parameters x and y and returns their sum in TypeScript?

calculate(x, y);

calculate(x: number, y: number);

How do you define a function greet that optionally takes a parameter name of type string and returns a greeting message in TypeScript?

function greet(name?: string): string { return Hello, ${name}!; }

function greet(name: string?): string { return Hello, ${name}!; }

function greet(name: string = 'Guest'): string { return Hello, ${name}!; }

function greet(name: string): string { return Hello, ${name}!; }

What is the purpose of using async/await in TypeScript?

To handle synchronous operations

To handle asynchronous operations more elegantly

To prevent callback hell

To improve performance

How do you call a function printInfo that optionally accepts parameters name (string) and age (number, default value 30) in TypeScript?

printInfo();

printInfo(name: string, age: number = 30);

printInfo(name?: string, age?: number);

What is a function signature in TypeScript?

The name of the function

The return type and parameter types of a function

The body of the function

The arguments passed to a function

What is the result of the following function call?

function greet(name: string = 'Guest'): string {
return Hello, ${name}!;
}
let message = greet();

"Hello, Guest!"

"Hello, undefined!"

"Hello,!"

Compilation Error

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