test("length is 1", () => { expect(Number).toHaveLength(1); }); test("constructor without new", () => { expect(typeof Number()).toBe("number"); expect(typeof new Number()).toBe("object"); expect(Number()).toBe(0); expect(Number(123)).toBe(123); expect(Number(-123)).toBe(-123); expect(Number(123n)).toBe(123); expect(Number(-123n)).toBe(-123); expect(Number("42")).toBe(42); expect(Number(null)).toBe(0); expect(Number(true)).toBe(1); expect(Number("Infinity")).toBe(Infinity); expect(Number("+Infinity")).toBe(Infinity); expect(Number("-Infinity")).toBe(-Infinity); expect(Number(undefined)).toBeNaN(); expect(Number({})).toBeNaN(); expect(Number({ a: 1 })).toBeNaN(); expect(Number([1, 2, 3])).toBeNaN(); expect(Number("foo")).toBeNaN(); }); test("constructor with new", () => { expect(typeof new Number()).toBe("object"); expect(new Number().valueOf()).toBe(0); expect(new Number(123).valueOf()).toBe(123); expect(new Number(-123).valueOf()).toBe(-123); expect(new Number(123n).valueOf()).toBe(123); expect(new Number(-123n).valueOf()).toBe(-123); expect(new Number("42").valueOf()).toBe(42); expect(new Number(null).valueOf()).toBe(0); expect(new Number(true).valueOf()).toBe(1); expect(new Number("Infinity").valueOf()).toBe(Infinity); expect(new Number("+Infinity").valueOf()).toBe(Infinity); expect(new Number("-Infinity").valueOf()).toBe(-Infinity); expect(new Number(undefined).valueOf()).toBeNaN(); expect(new Number({}).valueOf()).toBeNaN(); expect(new Number({ a: 1 }).valueOf()).toBeNaN(); expect(new Number([1, 2, 3]).valueOf()).toBeNaN(); expect(new Number("foo").valueOf()).toBeNaN(); });