Almost increasing sequence challenge from CodeSignal

almostIncreasingSequence.js

// Tests if an array is strictly increasing
const isIncreasing = xs =>
  xs.reduce((acc, x, i) => (i > 0 ? acc && x > xs[i - 1] : true), true)

// Drops the element at a given index from a given array
const dropAtIndex = i => xs => xs.filter((_, j) => i !== j)

// Returns all the elements except for the first
const tail = ([_, ...xs]) => xs

function almostIncreasingSequence(sequence) {
  const i = tail(sequence).findIndex((x, j) => x <= sequence[j])
  return (
    isIncreasing(dropAtIndex(i)(sequence)) ||
    isIncreasing(dropAtIndex(i + 1)(sequence))
  )
}