| // 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; |
