ValidateSubsequence.js

/* Given two non-empty arrays of integers, write a function that determines whether the second 
array is a subsequence of the first one.

A subsequence of an array is a set of numbers that aren't necessarily adjacent in the array 
but that are in the same order as they appear in the array. For instance, the numbers [1, 3, 4] 
form a subsequence of the array [1, 2, 3, 4], and so do the numbers [2, 4]. Note that a single 
number in an array and the array itself are both valid subsequences of the array.

Sample Input
array = [5, 1, 22, 25, 6, -1, 8, 10]
sequence = [1, 6, -1, 10]
Sample Output
true */

function isValidSubsequence(array, sequence) {
    if(sequence.length > array.length) {
      return false 
    } else {
      let seqIndex = 0
      for (const val of array) {
        if (val === sequence[seqIndex]) {
          seqIndex++
        }
      }
      return seqIndex === sequence.length ? true : false
    }
}

console.log(isValidSubsequence([5, 1, 22, 25, 6, -1, 8, 10], [1, 6, -1, 5]))