How can I reverse an array in JavaScript without using libraries?

Question

I am saving some data in order using arrays, and I want to add a function that the user can reverse the list. I can\'t think of any possible method, so if anybo

Answer 1

What about without using push() !

Solution using XOR !

var myARray = [1,2,3,4,5,6,7,8];

function rver(x){
    var l = x.length;
    for(var i=0; i<Math.floor(l/2); i++){

        var a = x[i];
        var b = x[l-1-i];

        a = a^b;
        b = b^a;
        a = a^b;

        x[i] = a;
        x[l-1-i] = b;
    }

    return x;

}

console.log(rver(myARray));

Answer 2

> var arr = [1,2,3,4,5,6];
> arr.reverse();
  [6, 5, 4, 3, 2, 1]

Answer 3

This is what you want:

array.reverse();

DEMO

Answer 4

Pure functions to reverse an array using functional programming:

var a = [3,5,7,8];

// ES2015
function immutableReverse(arr) {
  return [ ...a ].reverse();
}

// ES5
function immutableReverse(arr) {
  return a.concat().reverse()
}

Answer 5

function reverseArray(arr) {
    let reversed = [];
    for (i = 0; i < arr.length; i++) { 
    reversed.push((arr[arr.length-1-i]))
    }
  return reversed;
}

Answer 6

**

Shortest reverse array method without using reverse method:

**

 var a = [0, 1, 4, 1, 3, 9, 3, 7, 8544, 4, 2, 1, 2, 3];

 a.map(a.pop,[...a]); 
// returns [3, 2, 1, 2, 4, 8544, 7, 3, 9, 3, 1, 4, 1, 0]

a.pop method takes an last element off and puts upfront with spread operator ()

MDN links for reference:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/pop