describe('Number', function () { 'use strict'; describe('#toFixed()', function () { it('should convert numbers correctly', function () { expect((0.00008).toFixed(3)).toBe('0.000'); expect((0.9).toFixed(0)).toBe('1'); expect((1.255).toFixed(2)).toBe('1.25'); expect((1843654265.0774949).toFixed(5)).toBe('1843654265.07749'); expect((1000000000000000128).toFixed(0)).toBe('1000000000000000128'); }); }); describe('#toPrecision()', function () { // the spec allows for this test to fail. it('throws a RangeError when < 1 or > 21 (or > 100 in ES2018+)', function () { expect(function () { return (0.9).toPrecision(0); }).toThrow(); expect(function () { return [ (0.9).toPrecision(22), // ES2018 increased the limit from 21 to 100 (0.9).toPrecision(101) ]; }).toThrow(); }); it('works as expected', function () { expect((0.00008).toPrecision(3)).toBe('0.0000800'); expect((1.255).toPrecision(2)).toBe('1.3'); expect((1843654265.0774949).toPrecision(13)).toBe('1843654265.077'); expect(NaN.toPrecision(1)).toBe('NaN'); }); it('works with an undefined precision', function () { var num = 123.456; expect(num.toPrecision()).toBe(String(num)); expect(num.toPrecision(undefined)).toBe(String(num)); }); }); describe('constants', function () { it('should have MAX_VALUE', function () { expect(Number.MAX_VALUE).toBe(1.7976931348623157e308); }); it('should have MIN_VALUE', function () { expect(Number.MIN_VALUE).toBe(5e-324); }); it('should have NaN', function () { expect(Number.NaN).not.toBe(Number.NaN); }); it('should have POSITIVE_INFINITY', function () { expect(Number.POSITIVE_INFINITY).toBe(Infinity); }); it('should have NEGATIVE_INFINITY', function () { expect(Number.NEGATIVE_INFINITY).toBe(-Infinity); }); }); });