src/builtins/promise-try.tq

// Copyright 2024 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

namespace promise {

// https://tc39.es/proposal-promise-try/#sec-promise.try
@incrementUseCounter('v8::Isolate::kPromiseTry')
transitioning javascript builtin PromiseTry(
    js-implicit context: Context, receiver: JSAny)(...arguments): JSAny {
  // 1. Let C be the this value.
  // 2. If C is not an Object, throw a TypeError exception.
  const receiver = Cast<JSReceiver>(receiver)
      otherwise ThrowTypeError(MessageTemplate::kCalledOnNonObject, 'Promise.try');

  // 3. Let promiseCapability be ? NewPromiseCapability(C).
  const capability = NewPromiseCapability(receiver, False);

  // 4. Let status be Completion(Call(callbackfn, undefined, args)).
  const callbackfn = arguments[0];
  let result: JSAny;
  try {
    if (arguments.length <= 1) {
      result = Call(context, callbackfn, Undefined);
    } else {
      const rest = NewRestArgumentsFromArguments(arguments, 1);
      result = Call(
          context, GetReflectApply(), Undefined, callbackfn, Undefined, rest);
    }
  } catch (e, _message) {
    // 5. If status is an abrupt completion, then
    //   a. Perform ? Call(promiseCapability.[[Reject]], undefined, «
    //      status.[[Value]] »).
    Call(context, UnsafeCast<Callable>(capability.reject), Undefined, e);

    // 7. Return promiseCapability.[[Promise]].
    return capability.promise;
  }

  // 6. Else,
  //   a. Perform ? Call(promiseCapability.[[Resolve]], undefined, «
  //      status.[[Value]] »).
  Call(context, UnsafeCast<Callable>(capability.resolve), Undefined, result);

  // 7. Return promiseCapability.[[Promise]].
  return capability.promise;
}

}  // namespace promise