useList.ts

import type { Ref } from 'vue'
import { computed, ref } from 'vue'

export function useList<T>(initialValue: T[] = []) {
  const items = ref(initialValue) as Ref<T[]>
  const isEmpty = computed(() => items.value.length === 0)
  const size = computed(() => items.value.length)

  function enqueue(item: T) {
    items.value.push(item)
  }

  function dequeue(): T | null {
    return isEmpty.value ? null : items.value.shift()!
  }

  function front(): T | null {
    return isEmpty.value ? null : items.value[0]
  }

  function rear(): T | null {
    return isEmpty.value ? null : items.value.at(-1)!
  }

  function at(index: number): T | null {
    return items.value.at(index) ?? null
  }

  function has(item: T): boolean {
    return items.value.includes(item)
  }

  function insert(index: number, item: T): void {
    // TODO: test it
    if (index >= 0 && index <= size.value)
      items.value.splice(index, 0, item)
  }

  function remove(index: number): T | null {
    // TODO: test it
    if (index >= 0 && index < size.value)
      return items.value.splice(index, 1)[0] || null

    return null
  }

  function clear() {
    items.value = []
  }

  return {
    items,
    isEmpty,
    enqueue,
    dequeue,
    front,
    rear,
    at,
    has,
    insert,
    remove,
    size,
    clear,
  }
}