Reverse an Array in Javascript

Optimized for space

const reverseArray1 = arr => {
  let i = 0;
  let j = arr.length-1;
  let temp;
  while (i < j) {
    temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
    i++;
    j--;
  }
  return arr;
}

Optimized for processing

const reverseArray2 = arr => {
  const result = [];
  for(let i=arr.length-1; i>-1; i--) {
    result.push(arr[i]);
  }
  return result;
}

Example Input

console.log(reverseArray1([1,2,undefined,3,NaN,4,5,null,6,7,"str",8,9,0]));
console.log(reverseArray2([1,2,undefined,3,NaN,4,5,null,6,7,"str",8,9,0]));

Output

[ 0, 9, 8, 'str', 7, 6, null, 5, 4, NaN, 3, undefined, 2, 1 ]
[ 0, 9, 8, 'str', 7, 6, null, 5, 4, NaN, 3, undefined, 2, 1 ]

Comments

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