Five Ways to Reverse an Array in Javascript

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Oct 26, 2019

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We can reverse an array by both modifying the source array or without modifying the source array. We will look at different ways to do each.

Reversing an array by modifying the source array

We can use the reverse method available to JavaScript arrays.

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];
  
numbers.reverse();
  
console.log(numbers); // [5️⃣, 4️⃣, 3️⃣, 2️⃣, 1️⃣] 

Reversing without modifying the original array

1.Using a normal for loop

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];var reversedNum = [];for(let i =  numbers.length -1; i >= 0; i--) {  reversedNum.push(numbers[i]);
  
}

2. Using the map method with the unshift array method. unshift pushes the value to the 0th position of the array.

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];var reversedNum = [];
  
numbers.map((val) => {    reversedNum.unshift(val);});

3. Using slice and reverse

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];
   
var reversedNumbers = numbers.slice().reverse();

4. Using the spread operator and reverse

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];
   
var reversedNumbers = [...numbers].reverse();

5. Using the spread operator and reduce

var numbers = [ '1️⃣' , '2️⃣', '3️⃣', '4️⃣', '5️⃣' ];
  
let reversedArray = [];numbers.reduce( (reversedArray, value) => {   return [value , ...reversedArray];}, reversedArray);

There are manymore other ways to reverse an array in JS. Share your favorite or most interesting way to do it in the comments.

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