ladybird/Libraries/LibJS/Tests/operators/instanceof-basic.js

load("test-common.js");

try {
  function Foo() {
    this.x = 123;
  }

  var foo = new Foo();
  assert(foo instanceof Foo);

  function Base() {
    this.is_base = true;
  }

  function Derived() {
    this.is_derived = true;
  }

  Object.setPrototypeOf(Derived.prototype, Base.prototype);

  var d = new Derived();
  assert(d instanceof Derived);
  assert(d instanceof Base);

  console.log("PASS");
} catch (e) {
  console.log("FAIL: " + e);
}