39 lines
1.2 KiB
JavaScript
39 lines
1.2 KiB
JavaScript
describe("[[IsExtensible]] trap normal behavior", () => {
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test("forwarding when not defined in handler", () => {
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expect(Object.isExtensible(new Proxy({}, { isExtensible: null }))).toBeTrue();
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expect(Object.isExtensible(new Proxy({}, { isExtensible: undefined }))).toBeTrue();
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expect(Object.isExtensible(new Proxy({}, {}))).toBeTrue();
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});
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test("correct arguments supplied to trap", () => {
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let o = {};
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let p = new Proxy(o, {
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isExtensible(target) {
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expect(target).toBe(o);
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return true;
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},
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});
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expect(Object.isExtensible(p)).toBeTrue();
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});
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});
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describe("[[Call]] invariants", () => {
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test("return value must match the target's extensibility", () => {
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let o = {};
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Object.preventExtensions(o);
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let p = new Proxy(o, {
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isExtensible() {
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return true;
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},
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});
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expect(() => {
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Object.isExtensible(p);
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}).toThrowWithMessage(
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TypeError,
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"Proxy handler's isExtensible trap violates invariant: return value must match the target's extensibility"
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);
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});
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});
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