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

Functional tools for JS arrays

import { flatMap } from "./index"

describe("Array flatMap", () => {
  it("provides functional wrapper for Array.prototype.flatMap", () => {
    const arr = [1, 2, 3]
    const mappingFn = (x) => [x, x + 1]

    const result = flatMap(mappingFn, arr)
    const result2 = flatMap(mappingFn)(arr)
    // @ts-ignore
    const expected = arr.flatMap(mappingFn)

    expect(result).toEqual(result2)
    expect(result).toEqual(expected)
  })
})