JavaScript Methods

Question 1

concat()

Answer 1

Joins two or more arrays, and returns a copy of the joined arrays

Question 2

copyWithin()

Answer 2

Copies array elements within the array, to and from specified positions

Question 3

entries()

Answer 3

Returns a key/value pair Array Iteration Object

Question 4

every()

Answer 4

Checks if every element in an array pass a test

Question 5

fill()

Answer 5

Fill the elements in an array with a static value

Question 6

filter()

Answer 6

Creates a new array with every element in an array that pass a test

Question 7

find()

Answer 7

Returns the value of the first element in an array that pass a test

Question 8

findIndex()

Answer 8

Returns the index of the first element in an array that pass a test

Question 9

forEach()

Answer 9

Calls a function for each array element

Question 10

from()

Answer 10

Creates an array from an object

Question 11

includes()

Answer 11

Check if an array contains the specified element

Question 12

indexOf()

Answer 12

Search the array for an element and returns its position

Question 13

isArray()

Answer 13

Checks whether an object is an array

Question 14

join()

Answer 14

Joins all elements of an array into a string

Question 15

keys()

Answer 15

Returns a Array Iteration Object, containing the keys of the original array

Question 16

lastIndexOf()

Answer 16

Search the array for an element, starting at the end, and returns its position

Question 17

map()

Answer 17

Creates a new array with the result of calling a function for each array element

Question 18

pop()

Answer 18

Removes the last element of an array, and returns that element

Question 19

push()

Answer 19

Adds new elements to the end of an array, and returns the new length

Question 20

reduce()

Answer 20

Reduce the values of an array to a single value (going left-to-right)

Question 21

reduceRight()

Answer 21

Reduce the values of an array to a single value (going right-to-left)

Question 22

reverse()

Answer 22

Reverses the order of the elements in an array

Question 23

shift()

Answer 23

Removes the first element of an array, and returns that element

Question 24

slice()

Answer 24

Selects a part of an array, and returns the new array

Question 25

some()

Answer 25

Checks if any of the elements in an array pass a test

Question 26

sort()

Answer 26

Sorts the elements of an array

Question 27

splice()

Answer 27

Adds/Removes elements from an array

Question 28

toString()

Answer 28

Converts an array to a string, and returns the result

Question 29

unshift()

Answer 29

Adds new elements to the beginning of an array, and returns the new length

Question 30

valueOf()

Answer 30

Returns the primitive value of an array