referential-equality.test.js

describe("Referential Equality", () => {

  function foo() {
    return 'bar';
  }

  const otherFoo = function() {
    return `bar`;
  };

  const anotherFoo = () => 'bar';

  describe("Loose Equality", () => {
    test('Compare two strings',() => {
      const point_a = 'hello'
      const point_b = 'hello'
      expect(point_a==point_b).toBeTruthy();
    });
    test('Compare fn',() => {
      expect(foo==otherFoo).toBeFalsy();
    });
    test('two distinct objects are never equal',() => {
      const point_a = {}
      const point_b = {}
      expect(point_a==point_b).toBeFalsy();
    });
  });

  describe("Object Equality", () => {
    test('Compare Objects',() => {
      let point_a = {}
      let point_b = {}
      expect(Object.is(point_a, point_b)).toBeFalsy();
    });
  });

  describe("Strict Equality", () => {
    const fooReference = foo;
    test('Commpare two strings',() => {
      const point_a = 'hello'
      const point_b = 'hello'
      expect(point_a===point_b).toBeTruthy();
    });

    test('Compare same fn definition',() => {
      expect(foo===foo).toBeTruthy();
    });
    test('Compare same return value but different defs fn',() => {
      expect(foo===otherFoo).toBeFalsy();
    });
    test('Compare fn',() => {
      expect(foo===anotherFoo).toBeFalsy();
    });
    test('Compare fn and referenced var',() => {
      expect(foo === fooReference).toBeTruthy();
    });
  });
});