sliceArray.js

sliceArray.js

const arr = [1, 2, 3, 4, 5]
const pos = 2
const el = [10,11,12,13]
const slice = (arr) => (start) => (end) => [].concat(arr.slice(start, end))
const value = (el) => [].concat(el)

const insert = (arr) => (pos) => (el) => {
  
    return [...slice(arr)(0)(pos), ...value(el), ...slice(arr)(pos)()]

} 
const insertArr = insert(arr)
const insertPos = insertArr(pos)
const insertEl = insertPos(el)
const result = insertEl

console.log(result) //[ 1, 2, 10, 11, 12, 13, 3, 4, 5 ]