71 lines
2.1 KiB
JavaScript
71 lines
2.1 KiB
JavaScript
test("length is 1", () => {
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expect(Object.seal).toHaveLength(1);
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});
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describe("normal behavior", () => {
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test("returns given argument", () => {
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const o = {};
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expect(Object.seal(42)).toBe(42);
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expect(Object.seal("foobar")).toBe("foobar");
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expect(Object.seal(o)).toBe(o);
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});
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test("prevents addition of new properties", () => {
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const o = {};
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expect(o.foo).toBeUndefined();
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Object.seal(o);
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o.foo = "bar";
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expect(o.foo).toBeUndefined();
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});
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test("prevents deletion of existing properties", () => {
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const o = { foo: "bar" };
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expect(o.foo).toBe("bar");
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Object.seal(o);
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delete o.foo;
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expect(o.foo).toBe("bar");
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});
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test("prevents changing attributes of existing properties", () => {
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const o = { foo: "bar" };
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Object.seal(o);
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expect(Object.defineProperty(o, "foo", {})).toBe(o);
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expect(Object.defineProperty(o, "foo", { configurable: false })).toBe(o);
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expect(() => {
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Object.defineProperty(o, "foo", { configurable: true });
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}).toThrowWithMessage(TypeError, "Object's [[DefineOwnProperty]] method returned false");
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});
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test("doesn't prevent changing value of existing properties", () => {
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const o = { foo: "bar" };
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expect(o.foo).toBe("bar");
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Object.seal(o);
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o.foo = "baz";
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expect(o.foo).toBe("baz");
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});
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// #6469
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test("works with indexed properties", () => {
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const a = ["foo"];
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expect(a[0]).toBe("foo");
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Object.seal(a);
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a[0] = "bar";
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a[1] = "baz";
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expect(a[0]).toBe("bar");
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expect(a[1]).toBeUndefined();
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});
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test("works with properties that are already non-configurable", () => {
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const o = {};
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Object.defineProperty(o, "foo", {
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value: "bar",
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configurable: false,
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writable: true,
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enumerable: true,
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});
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expect(o.foo).toBe("bar");
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Object.seal(o);
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o.foo = "baz";
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expect(o.foo).toBe("baz");
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});
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});
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