| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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. |
| */ |
| |
| /** |
| * 统一promise的错误处理机制 |
| * 在使用async/await的过程中，对于错误的处理，通常第一选择是try/catch, |
| * 但是常常会出现nested try/catch，代码就不会那么优雅 |
| * 针对异常或者异常的处理有很多方式，命令式的try/catch, 函数式的Optional, Either |
| * 还比如go的多返回值， |
| * f, err := os.Open("filename.ext") |
| * if err != nil { |
| * log.Fatal(err) |
| * } |
| * 虽然verbose但是足够简单，规则统一 |
| * |
| * 所以在这里对promise的错误处理进行值的统一包装，以此来简化 |
| * |
| * Usage: |
| * function test() { |
| * return new Promise((resolve, reject) => { |
| * setTimeout(() => { |
| * resolve('hello'); |
| * //reject(new Error('error')) |
| * }, 200) |
| * }) |
| * } |
| * |
| * (async () => { |
| * const {res, err} = await to(test()); |
| * console.log(res) ;// hello |
| * console.log(err); //Error('error') |
| * })(); |
| * |
| * @param promise |
| */ |
| export function to<T>(promise: Promise<T>): Promise<{err: Error; res: T}> { |
| return promise.then((res: T = null) => ({res, err: null})).catch(err => ({ |
| res: null, |
| err, |
| })); |
| } |
