ladybird/Libraries/LibJS/Tests/operators/instanceof-basic.js
Linus Groh 565a26808d LibJS: Fix crashing exception in Value::ordinary_has_instance()
Two issues:

- throw_exception() with ErrorType::InstanceOfOperatorBadPrototype would
  receive rhs_prototype.to_string_without_side_effects(), which would
  ASSERT_NOT_REACHED() as to_string_without_side_effects() must not be
  called on an empty value. It should (and now does) receive the RHS
  value instead as the message is "'prototype' property of {} is not an
  object".
- Value::instance_of() was missing an exception check after calling
  has_instance_method, to_boolean() on an empty value result would crash
  as well.

Fixes #3930.
2020-11-03 19:14:13 +01:00

36 lines
750 B
JavaScript

test("basic functionality", () => {
function Foo() {
this.x = 123;
}
const foo = new Foo();
expect(foo instanceof Foo).toBeTrue();
});
test("derived ES5 classes", () => {
function Base() {
this.is_base = true;
}
function Derived() {
this.is_derived = true;
}
Object.setPrototypeOf(Derived.prototype, Base.prototype);
const d = new Derived();
expect(d instanceof Derived).toBeTrue();
expect(d instanceof Base).toBeTrue();
});
test("issue #3930, instanceof on arrow function", () => {
function f() {}
const a = () => {};
expect(() => {
f instanceof a;
}).toThrow(TypeError);
expect(() => {
a instanceof a;
}).toThrow(TypeError);
});