JS list vs array benchmark for adding and removing elements at the head.

list-bench.js

import b from "benny"

const SIZE = 100_000

let list = {}

for (let i = SIZE; i > 0; i--) {
  list = !list.value ? { value: i, rest: null } : { value: i, rest: list }
}

const arr = Array.from({ length: SIZE }, (_, i) => i + 1)

await b.suite(
  `Head operations (${SIZE} elements initially)`,

  b.add("list", () => {
    list = list.rest
    list = {
      value: Math.random(),
      rest: list,
    }
  }),

  b.add("array", () => {
    arr.shift()
    arr.unshift(Math.random())
  }),

  b.cycle(),
  b.complete(),
)

console.log(list.value, arr[0])