ladybird/Userland/Libraries/LibJS/Tests/operators/instanceof-basic.js
2021-01-12 12:17:46 +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);
});