42 lines
1.3 KiB
JavaScript
42 lines
1.3 KiB
JavaScript
test("length is 2", () => {
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expect(Object.assign).toHaveLength(2);
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});
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describe("errors", () => {
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test("first argument must coercible to object", () => {
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expect(() => {
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Object.assign(null);
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}).toThrowWithMessage(TypeError, "ToObject on null or undefined");
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expect(() => {
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Object.assign(undefined);
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}).toThrowWithMessage(TypeError, "ToObject on null or undefined");
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});
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});
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describe("normal behavior", () => {
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test("returns first argument coerced to object", () => {
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const o = {};
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expect(Object.assign(o)).toBe(o);
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expect(Object.assign(o, {})).toBe(o);
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expect(Object.assign(42)).toEqual(new Number(42));
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});
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test("alters first argument object if sources are given", () => {
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const o = { foo: 0 };
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expect(Object.assign(o, { foo: 1 })).toBe(o);
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expect(o).toEqual({ foo: 1 });
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});
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test("merges objects", () => {
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const s = Symbol();
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expect(
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Object.assign(
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{},
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{ foo: 0, bar: "baz" },
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{ [s]: [1, 2, 3] },
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{ foo: 1 },
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{ [42]: "test" }
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)
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).toEqual({ foo: 1, bar: "baz", [s]: [1, 2, 3], 42: "test" });
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});
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});
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