Reversing an array in JavaScript can be done in several ways depending on the specific use case. Below, I’ll show all major types of examples

 

. Using the Built-in .reverse() Method

This is the simplest and most direct way.

javascript

let arr = [1, 2, 3, 4, 5];
arr.reverse();
console.log(arr); // [5, 4, 3, 2, 1]

⚠️ This method mutates the original array.

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🔁 2. Using the Spread Operator & .reverse() (Non-mutating)

To avoid changing the original array:

javascript

let arr = [1, 2, 3, 4, 5];
let reversed = [...arr].reverse();
console.log(reversed); // [5, 4, 3, 2, 1]
console.log(arr); // [1, 2, 3, 4, 5] — unchanged

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🔁 3. Using a for Loop

Manual reverse using a classic for loop:

javascript

let arr = [1, 2, 3, 4, 5];
let reversed = [];

for (let i = arr.length - 1; i >= 0; i--) {
    reversed.push(arr[i]);
}
console.log(reversed); // [5, 4, 3, 2, 1]

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🔁 4. Using a while Loop

javascript

let arr = [1, 2, 3, 4, 5];
let reversed = [];
let i = arr.length - 1;

while (i >= 0) {
    reversed.push(arr[i]);
    i--;
}
console.log(reversed); // [5, 4, 3, 2, 1]

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🔁 5. Using Recursion

A functional way to reverse an array:

javascript

function reverseArray(arr) {
    if (arr.length === 0) return [];
    return [arr.pop()].concat(reverseArray(arr));
}

let arr = [1, 2, 3, 4, 5];
console.log(reverseArray([...arr])); // [5, 4, 3, 2, 1]

🔁 This also mutates the original if not cloned with [...arr].

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🔁 6. Using reduceRight()

A more functional-style approach:

javascript

let arr = [1, 2, 3, 4, 5];
let reversed = arr.reduceRight((acc, curr) => {
    acc.push(curr);
    return acc;
}, []);

console.log(reversed); // [5, 4, 3, 2, 1]

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🔁 7. Swapping Elements In-Place

This doesn't use extra space and is optimal for large arrays:

javascript

let arr = [1, 2, 3, 4, 5];

for (let i = 0; i < arr.length / 2; i++) {
    let temp = arr[i];
    arr[i] = arr[arr.length - 1 - i];
    arr[arr.length - 1 - i] = temp;
}

console.log(arr); // [5, 4, 3, 2, 1]

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Summary Table:

Method	Mutates?	Extra Space	Notes
.reverse()	✅	❌	Simple, in-place
[...arr].reverse()	❌	✅	Clones, safer
for/while loop	❌	✅	Good for manual control
Recursion	✅ or ❌	✅	Elegant but less efficient
reduceRight()	❌	✅	Functional-style
In-place swap	✅	❌	Optimal for performance