Group elemnts of array, skiping last N elements in group

group-with-skip.js

function groupSkip(arr, shift, skip = 1) {
    const res = []
    let limit = 0
    while (limit+shift <= arr.length) {
      res.push(arr.slice(limit, shift + limit - skip))
      limit += shift
    }
    return res
}

const res = groupSkip(array, 4)