All Questions

ES6+ Features Interview Questions

MCQ Question 1 of 10

What is the main difference between let and var?

let has block scope, var has function scopelet allows redeclaration, var does notlet is hoisted, var is notNo difference

Which statement about const is correct?

const variables cannot be reassignedconst variables are immutable objectsconst can be redeclaredconst variables are not hoisted

How do you create a string using template literals?

"Hello ${name}"'Hello ${name}'`Hello ${name}`<Hello ${name}>

What will add(5) return if the function is defined as:

function add(a, b = 10) { return a + b; }

NaNundefined1510

Which statement is true about arrow functions?

They have their own thisCannot be used as anonymous functionsThey do not have their own thisCannot return values

What is the value of x after this code?

let [x, y] = [10, 20];

undefined1020[10, 20]

What does the following produce?

let arr1 = [1, 2];
let arr2 = [...arr1, 3, 4];

[1, 2, [3, 4]][1, 2, 3, 4][[1, 2], 3, 4][3, 4, 1, 2]

What is the shorthand syntax for { name: name, age: age }?

{ name, age }{ name => name, age => age }{ name: age }{ name, age: age }

Which function correctly uses rest parameters to accept multiple arguments?

function sum(...nums) {}function sum(...nums, extra) {}function sum(nums...) {}function sum(...nums[]) {}

How do you export a function in ES6 module?

export function myFunc() {}module.exports = myFunc;export default myFunc;Both A and C