ladybird/Libraries/LibJS/Tests/builtins/Object/Object.keys.js

describe("correct behavior", () => {
  test("length", () => {
    expect(Object.keys).toHaveLength(1);
    expect(Object.keys(true)).toHaveLength(0);
    expect(Object.keys(45)).toHaveLength(0);
    expect(Object.keys(-998)).toHaveLength(0);
    expect(Object.keys("abcd")).toHaveLength(4);
    expect(Object.keys([1, 2, 3])).toHaveLength(3);
    expect(Object.keys({ a: 1, b: 2, c: 3 })).toHaveLength(3);
  });

  test("object argument", () => {
    let keys = Object.keys({ foo: 1, bar: 2, baz: 3 });
    expect(keys).toEqual(["foo", "bar", "baz"]);
  });

  test("array argument", () => {
    let keys = Object.keys(["a", "b", "c"]);
    expect(keys).toEqual(["0", "1", "2"]);
  });

  test("ignores non-enumerable properties", () => {
    let obj = { foo: 1 };
    Object.defineProperty(obj, "getFoo", {
      value: function () {
        return this.foo;
      },
    });
    keys = Object.keys(obj);
    expect(keys).toEqual(["foo"]);
  });
});

describe("errors", () => {
  test("null argument value", () => {
    expect(() => {
      Object.keys(null);
    }).toThrowWithMessage(TypeError, "ToObject on null or undefined");
  });

  test("undefined argument value", () => {
    expect(() => {
      Object.keys(undefined);
    }).toThrowWithMessage(TypeError, "ToObject on null or undefined");
  });
});