Duplicate Zeros LeetCode solution in JavaScript

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/**
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 * @param {number[]} arr
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 * @return {void} Do not return anything, modify arr in-place instead.
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 */
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var duplicateZeros = function (arr) {
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  // Variables
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  const originalLength = arr.length;
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  // Iterate over all the numbers in 'arr', if the number is 0 we duplicate it and skip the next loop iteration to prevent an overflow.
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  for (let idx = 0; idx < arr.length; idx++) {
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    const number = arr[idx];
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    if (number === 0) {
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      arr.splice(idx, 0, 0);
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      idx += 1;
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    }
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  }
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  // Here we restore the array to its original length.
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  return (arr.length = originalLength);
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};