memoize.spec.js - mozsearch

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */

import memoize from "../memoize";

const a = { number: 3 };

const b = { number: 4 };

const c = { number: 5 };

const d = { number: 6 };

function add(...numberObjects) {

  return numberObjects.reduce((prev, cur) => prev + cur.number, 0);

describe("memozie", () => {

  it("should work for one arg as key", () => {

    const mAdd = memoize(add);

    mAdd(a);

    expect(mAdd(a)).toEqual(3);

    mAdd(b);

    expect(mAdd(b)).toEqual(4);

});

  it("should only be called once", () => {

    const spy = jest.fn(() => 2);

    const mAdd = memoize(spy);

    mAdd(a);

    mAdd(a);

    mAdd(a);

    expect(spy).toHaveBeenCalledTimes(1);

});

  it("should work for two args as key", () => {

    const mAdd = memoize(add);

    expect(mAdd(a, b)).toEqual(7);

    expect(mAdd(a, b)).toEqual(7);

    expect(mAdd(a, c)).toEqual(8);

});

  it("should work with many args as key", () => {

    const mAdd = memoize(add);

    expect(mAdd(a, b, c)).toEqual(12);

    expect(mAdd(a, b, d)).toEqual(13);

    expect(mAdd(a, b, c)).toEqual(12);

});

});