jslol

types.spec.js

const assert = require('assert');

describe('typeof', () => {
    it('arrays are objects', () => {
        assert(typeof [] === 'object');
    });

    it('objects are objects', () => {
        assert(typeof {} === 'object');
    });

    it('strings are strings', () => {
        assert(typeof '' === 'string');
    });

    it('numbers are numbers', () => {
        assert(typeof 0 === 'number');
    });

    it('booleans are booleans', () => {
        assert(typeof false === 'boolean');
    });

    it('NaN is a number', () => {
        assert(typeof NaN === 'number');
    });

    it('undefined is undefined', () => {
        assert(typeof undefined === 'undefined');
    });
});

describe('instanceof', () => {
    it('arrays are Arrays', () => {
        assert([] instanceof Array);
    });

    it('objects are Objects', () => {
        assert({} instanceof Object);
    });

    it('strings are not Strings', () => {
        assert(!('' instanceof String));
    });

    it('numbers are not Numbers', () => {
        assert(!(0 instanceof Number));
    });

    it('booleans are not Booleans', () => {
        assert(!(false instanceof Boolean));
    });
});

describe('comparison', () => {
    describe('double equals', () => {
        it('the string 2 is equal to the number 2', () => {
            assert('2' == 2);
            assert(2 == '2');
        });

        it('the string 2 is equal to the string 2', () => {
            assert('2' == '2');
        });

        it('the number 2 is equal to the number 2', () => {
            assert(2 == 2);
        });

        it('the array [1, 2, 3] is not equal to the array [1, 2, 3]', () => {
            assert(!([1, 2, 3] == [1, 2, 3]));
        });
    });

    it('the string 1 plus the number 1 is the string 11', () => {
        assert.equal('1' + 1, '11');
        assert.equal(1 + '1', '11');
    });

    it('the string 2 divided by the number 2 is the number 1', () => {
        assert.equal('2' / 2, 1);
        assert.equal(2 / '2', 1);
    });

    it('the string true and the boolean true is the boolean true', () => {
        assert('true' && true);
        assert(true && 'true');
    });

    it('the string true and the string true is the boolean true', () => {
        assert('true' && 'true');
    });

    it('the string 1 and the boolean true is the boolean true', () => {
        assert('1' && true);
        assert(true && '1');
    });

    it('the string true or the boolean false is the boolean true', () => {
        assert('true' || false);
        assert(false || 'true');
    });

    it('the string 1 or the boolean false is the boolean true', () => {
        assert(false || '1');
    });
});