JavaScript - POP, PUSH,SHIFT and UNSHIFT

POP : The pop() method removes the last element from an array and returns it.

var numbers = [0,1,2,3,4];

//remove last number
console.log(numbers.pop()); //4

//new array
console.log(numbers); //output - [0,1,2,3]

PUSH : The push() method adds a new elemnet at the end of an array and returns the new array length.

var numbers = [0,1,2,3,4];

//add number at the end
//6 is the length of the new array
console.log(numbers.push(5)); //6

//new array
console.log(numbers); //output - [0,1,2,3,4,5]

SHIFT : The shift() method removes the first array element of an array and returns it.

var numbers = [0,1,2,3,4];

//remove number at the beginning
//returns removed number
console.log(numbers.shift()); //0

//new array
console.log(numbers); //output - [1,2,3,4]

UNSHIFT : The unshift() method adds a new element to at the beginning of an array and returns the new array length.

var numbers = [0,1,2,3,4];

//add the number at the beginning
//6 is the length of the new array
console.log(numbers.unshift(5)); //6

//new array
console.log(numbers); //output - [5,0,1,2,3,4]