30 Asked Interview Questions and Answers (2024)

Array.includes() is used to check if an array includes a certain element, returning true or false.

Example:

const numbers = [1, 2, 3, 4, 5]; const includesThree = numbers.includes(3);

Object.entries() is used to return an array of a given object's own enumerable string-keyed property [key, value] pairs.

Example:

const obj = { a: 1, b: 2 }; const entries = Object.entries(obj);

Object.keys() is used to return an array of a given object's own enumerable string-keyed property names.

Example:

const obj = { a: 1, b: 2 }; const keys = Object.keys(obj);

Object.values() is used to return an array of a given object's own enumerable string-keyed property values.

Example:

const obj = { a: 1, b: 2 }; const values = Object.values(obj);

The 'for...of' loop is used to iterate over values in an iterable object, such as an array, string, or Map.

Example:

const arr = [1, 2, 3]; for (const num of arr) { console.log(num); }

ES6 Interview Questions and Answers