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

Functional tools for JS arrays

import { zipWith_ } from "./index"

describe("Array zipAll", () => {
  it("returns correct pairs for arrays with equal length", () => {
    const arr = [1, 2, 3]
    const otherArr = [3, 4, 5]
    const zippingFn = (a, b) => a + b

    const result = zipWith_(zippingFn, otherArr, arr)
    const result2 = zipWith_(zippingFn, otherArr)(arr)
    const result3 = zipWith_(zippingFn)(otherArr, arr)
    const result4 = zipWith_(zippingFn)(otherArr)(arr)

    const expected = [4, 6, 8]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("returns correct pairs for when base array is shorter", () => {
    const arr = [1, 2]
    const otherArr = [3, 4, 5]
    const zippingFn = (a, b) => a + b

    const result = zipWith_(zippingFn, otherArr, arr)
    const result2 = zipWith_(zippingFn, otherArr)(arr)
    const result3 = zipWith_(zippingFn)(otherArr, arr)
    const result4 = zipWith_(zippingFn)(otherArr)(arr)

    const expected = [4, 6]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("returns correct pairs for when base array is longer", () => {
    const arr = [1, 2, 3]
    const otherArr = [3, 4]
    const zippingFn = (a, b) => a + b

    const result = zipWith_(zippingFn, otherArr, arr)
    const result2 = zipWith_(zippingFn, otherArr)(arr)
    const result3 = zipWith_(zippingFn)(otherArr, arr)
    const result4 = zipWith_(zippingFn)(otherArr)(arr)

    const expected = [4, 6]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("always returns a new array", () => {
    const arr = []
    const otherArr = []
    const zippingFn = (a, b) => a + b

    const result = zipWith_(zippingFn)(otherArr)(arr)

    expect(result).not.toBe(arr)
  })
})

describe("Array zipWith all", () => {
  it("returns correct pairs for arrays with equal length", () => {
    const arr = [1, 2, 3]
    const otherArr = [3, 4, 5]
    const zippingFn = (a, b) => a + b

    const result = zipWith_.all(zippingFn, otherArr, arr)
    const result2 = zipWith_.all(zippingFn, otherArr)(arr)
    const result3 = zipWith_.all(zippingFn)(otherArr, arr)
    const result4 = zipWith_.all(zippingFn)(otherArr)(arr)

    const expected = [4, 6, 8]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("returns correct pairs for when base array is shorter", () => {
    const arr = [1, 2]
    const otherArr = [3, 4, 5]
    const zippingFn = (a = 0, b = 0) => a + b

    const result = zipWith_.all(zippingFn, otherArr, arr)
    const result2 = zipWith_.all(zippingFn, otherArr)(arr)
    const result3 = zipWith_.all(zippingFn)(otherArr, arr)
    const result4 = zipWith_.all(zippingFn)(otherArr)(arr)

    const expected = [4, 6, 5]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("returns correct pairs for when base array is longer", () => {
    const arr = [1, 2, 3]
    const otherArr = [3, 4]
    const zippingFn = (a = 0, b = 0) => a + b

    const result = zipWith_.all(zippingFn, otherArr, arr)
    const result2 = zipWith_.all(zippingFn, otherArr)(arr)
    const result3 = zipWith_.all(zippingFn)(otherArr, arr)
    const result4 = zipWith_.all(zippingFn)(otherArr)(arr)

    const expected = [4, 6, 3]

    expect(result).toEqual(result2)
    expect(result).toEqual(result3)
    expect(result).toEqual(result4)
    expect(result).toEqual(expected)
  })

  it("always returns a new array", () => {
    const arr = []
    const otherArr = []
    const zippingFn = (a, b) => a + b

    const result = zipWith_.all(zippingFn)(otherArr)(arr)

    expect(result).not.toBe(arr)
  })
})