describe("normal functionality", () => { let s = Symbol("foo"); test("non-configurable string property", () => { let o = {}; Object.defineProperty(o, "foo", { value: 1, writable: false, enumerable: false }); expect(o.foo).toBe(1); o.foo = 2; expect(o.foo).toBe(1); expect(o).not.toHaveConfigurableProperty("foo"); expect(o).not.toHaveEnumerableProperty("foo"); expect(o).not.toHaveWritableProperty("foo"); expect(o).toHaveValueProperty("foo", 1); }); test("non-configurable symbol property", () => { let o = {}; Object.defineProperty(o, s, { value: 1, writable: false, enumerable: false }); expect(o[s]).toBe(1); o[s] = 2; expect(o[s]).toBe(1); expect(o).not.toHaveConfigurableProperty(s); expect(o).not.toHaveEnumerableProperty(s); expect(o).not.toHaveWritableProperty(s); expect(o).toHaveValueProperty(s, 1); }); test("array index getter", () => { let o = {}; Object.defineProperty(o, 2, { get() { return 10; }, }); expect(o[2]).toBe(10); }); test("symbol property getter", () => { let o = {}; Object.defineProperty(o, s, { get() { return 10; }, }); expect(o[s]).toBe(10); }); test("configurable string property", () => { let o = {}; Object.defineProperty(o, "foo", { value: "hi", writable: true, enumerable: true }); expect(o.foo).toBe("hi"); o.foo = "ho"; expect(o.foo).toBe("ho"); expect(o).not.toHaveConfigurableProperty("foo"); expect(o).toHaveEnumerableProperty("foo"); expect(o).toHaveWritableProperty("foo"); expect(o).toHaveValueProperty("foo", "ho"); }); test("configurable symbol property", () => { let o = {}; Object.defineProperty(o, s, { value: "hi", writable: true, enumerable: true }); expect(o[s]).toBe("hi"); o[s] = "ho"; expect(o[s]).toBe("ho"); expect(o).not.toHaveConfigurableProperty(s); expect(o).toHaveEnumerableProperty(s); expect(o).toHaveWritableProperty(s); expect(o).toHaveValueProperty(s, "ho"); }); test("reconfigure configurable string property", () => { let o = {}; Object.defineProperty(o, "foo", { value: 9, configurable: true, writable: false }); Object.defineProperty(o, "foo", { configurable: true, writable: true }); expect(o).toHaveConfigurableProperty("foo"); expect(o).toHaveWritableProperty("foo"); expect(o).not.toHaveEnumerableProperty("foo"); expect(o).toHaveValueProperty("foo", 9); }); test("reconfigure configurable symbol property", () => { let o = {}; Object.defineProperty(o, s, { value: 9, configurable: true, writable: false }); Object.defineProperty(o, s, { configurable: true, writable: true }); expect(o).toHaveConfigurableProperty(s); expect(o).toHaveWritableProperty(s); expect(o).not.toHaveEnumerableProperty(s); expect(o).toHaveValueProperty(s, 9); }); test("define string accessor", () => { let o = {}; Object.defineProperty(o, "foo", { configurable: true, get() { return o.secret_foo + 1; }, set(value) { this.secret_foo = value + 1; }, }); o.foo = 10; expect(o.foo).toBe(12); o.foo = 20; expect(o.foo).toBe(22); Object.defineProperty(o, "foo", { configurable: true, value: 4 }); expect(o.foo).toBe(4); expect((o.foo = 5)).toBe(5); expect((o.foo = 4)).toBe(4); }); test("define symbol accessor", () => { let o = {}; Object.defineProperty(o, s, { configurable: true, get() { return o.secret_foo + 1; }, set(value) { this.secret_foo = value + 1; }, }); o[s] = 10; expect(o[s]).toBe(12); o[s] = 20; expect(o[s]).toBe(22); Object.defineProperty(o, s, { configurable: true, value: 4 }); expect(o[s]).toBe(4); expect((o[s] = 5)).toBe(5); expect((o[s] = 4)).toBe(4); }); test("issue #3735, reconfiguring property in unique shape", () => { const o = {}; // In LibJS an object with more than 100 properties gets a unique shape for (let i = 0; i < 101; ++i) { o[`property${i}`] = i; } Object.defineProperty(o, "x", { configurable: true }); Object.defineProperty(o, "x", { configurable: false }); }); }); describe("errors", () => { test("redefine non-configurable property", () => { let o = {}; Object.defineProperty(o, "foo", { value: 1, writable: true, enumerable: true }); expect(() => { Object.defineProperty(o, "foo", { value: 2, writable: true, enumerable: false }); }).toThrowWithMessage(TypeError, "Object's [[DefineOwnProperty]] method returned false"); }); test("redefine non-configurable symbol property", () => { let o = {}; let s = Symbol("foo"); Object.defineProperty(o, s, { value: 1, writable: true, enumerable: true }); expect(() => { Object.defineProperty(o, s, { value: 2, writable: true, enumerable: false }); }).toThrowWithMessage(TypeError, "Object's [[DefineOwnProperty]] method returned false"); }); test("cannot define 'value' and 'get' in the same descriptor", () => { let o = {}; expect(() => { Object.defineProperty(o, "a", { get() {}, value: 9, }); }).toThrowWithMessage( TypeError, "Accessor property descriptor cannot specify a value or writable key" ); }); test("cannot define 'value' and 'set' in the same descriptor", () => { let o = {}; expect(() => { Object.defineProperty(o, "a", { set() {}, writable: true, }); }).toThrowWithMessage( TypeError, "Accessor property descriptor cannot specify a value or writable key" ); }); test("redefine non-configurable accessor", () => { let o = {}; Object.defineProperty(o, "foo", { configurable: false, get() { return this.secret_foo + 2; }, set(value) { o.secret_foo = value + 2; }, }); expect(() => { Object.defineProperty(o, "foo", { configurable: false, get() { return this.secret_foo + 2; }, }); }).toThrowWithMessage(TypeError, "Object's [[DefineOwnProperty]] method returned false"); }); });