How to find missing numbers in a sequence with JavaScript?

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To find missing numbers in a sequence in JavaScript, you can first sort the array and then iterate through it, comparing each value to the expected value. If a value is missing, you can add it to a separate array.

Here’s an example of finding missing numbers in an array of integers:

function findMissingNumbers(array) {
  array.sort((a, b) => a - b);
  let missingNumbers = [];
  for (let i = array[0]; i < array[array.length - 1]; i++) {
    if (array.indexOf(i) === -1) {
  return missingNumbers;

const array = [3, 7, 1, 2, 8, 4, 5];
console.log(findMissingNumbers(array)); // [6]

In this example, we first sort the input array in ascending order. Then, we iterate from the first element to the second to last element in the array and use the Array.indexOf() method to check if the current number is in the array. If it’s not, we add it to the missingNumbers array. Finally, we return the missingNumbers array, which contains the missing numbers in the sequence.

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