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LibJS: Implement Object.hasOwn() :^)

This is currently a TC39 Stage 2 proposal, but let's go for it!

https://github.com/tc39/proposal-accessible-object-hasownproperty

I wrote the C++, @linusg found bugs and wrote the test.
This commit is contained in:
Andreas Kling 2021-05-18 11:15:49 +02:00
parent 94569e52f5
commit 3ee092cd0c
4 changed files with 49 additions and 0 deletions

View file

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describe("basic functionality", () => {
test("length", () => {
expect(Object.hasOwn).toHaveLength(2);
});
test("returns true for existent own property", () => {
const o = { foo: "bar" };
expect(Object.hasOwn(o, "foo")).toBeTrue();
});
test("returns false for non-existent own property", () => {
const o = {};
expect(Object.hasOwn(o, "foo")).toBeFalse();
});
test("returns false for existent prototype chain property", () => {
const o = {};
Object.prototype.foo = "bar";
expect(Object.hasOwn(o, "foo")).toBeFalse();
});
});
describe("errors", () => {
test("null argument", () => {
expect(() => {
Object.hasOwn(null);
}).toThrowWithMessage(TypeError, "ToObject on null or undefined");
});
test("undefined argument", () => {
expect(() => {
Object.hasOwn(undefined);
}).toThrowWithMessage(TypeError, "ToObject on null or undefined");
});
});