ladybird/Libraries/LibJS/Tests/classes/class-constructor.js

test("property initialization", () => {
  class A {
    constructor() {
      this.x = 3;
    }
  }

  expect(new A().x).toBe(3);
});

test("method initialization", () => {
  class A {
    constructor() {
      this.x = () => 10;
    }
  }

  expect(new A().x()).toBe(10);
});

test("initialize to class method", () => {
  class A {
    constructor() {
      this.x = this.method;
    }

    method() {
      return 10;
    }
  }

  expect(new A().x()).toBe(10);
});

test("constructor length affects class length", () => {
  class A {
    constructor() {}
  }

  expect(A).toHaveLength(0);

  class B {
    constructor(a, b, c = 2) {}
  }

  expect(B).toHaveLength(2);
});

test.skip("must be invoked with 'new'", () => {
  class A {
    constructor() {}
  }

  expect(() => {
    A();
  }).toThrow(TypeError); // FIXME: Add message when this test works

  expect(() => {
    A.prototype.constructor();
  }).toThrow(TypeError); // FIXME: Add message when this test works
});

test("implicit constructor", () => {
  class A {}

  expect(new A()).toBeInstanceOf(A);
});