// Copyright (C) 2023 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Return true if value is not nullish - i.e. not null or undefined
// Allows doing the following
//   exists(val) && m('div', val)
// Even if val is a non-nullish falsey value like 0 or ''
export function exists<T>(value: T): value is NonNullable<T> {
  return value !== undefined && value !== null;
}

// Generic result type - similar to Rust's Result<T, E>
export type Result<T, E = {}> =
  | {success: true; result: T}
  | {success: false; error: E};

// Generic "optional" type
export type Optional<T> = T | undefined;