@arrows/array/src/first_.test.ts

Functional tools for JS arrays

import { first_ } from "./index"

describe("Array firstX", () => {
  it("returns first element of the array", () => {
    const arr = [1, 2, 3, 4]

    const result = first_(arr)
    const expected = 1

    expect(result).toEqual(expected)
  })

  it("returns undefined if array is empty", () => {
    const arr = []

    const result = first_(arr)
    const expected = undefined

    expect(result).toEqual(expected)
  })
})