Node.js 进程多重解析事件

原文:https://www . geesforgeks . org/node-js-process-multipleresolves-event/

“多重解析”是流程模块中的一个流程类事件，每当一个承诺被:

• 解决了不止一次。
• 被拒绝了不止一次。
• 解决后被拒绝。
• 拒绝后解决。

语法:

Event: 'multipleResolves'

参数:此事件不接受任何参数作为参数。

返回值:该事件只返回一个回调函数，用于进一步操作。

例 1:

index.js

// Node.js program to demonstrate the  
// Process 'multipleResolves' Event

// Importing process module
const process = require('process');

// Independent Block which will execute
setTimeout(() => {
   console.log('\n')
   console.log('Greetings from GeeksforGeeks');
}, 1000);

// Event 'multipleResolves' 
process.on('multipleResolves', (type, promise, reason) => {

   // Displaying the error 
   console.log("Type: ", type);
   console.log("Promsie: ", promise);
   console.log("Reason: ", reason);
});

const myFunction = async () => {
   const data = await new Promise((resolve, reject) => {

      // Calling reject after multiple resolve
      resolve('Resolve Call One');
      resolve('Resolve Call Two');
      resolve('Resolve Call Three');
      reject(new Error('Reject Error Called'));
   });
   return data
}

// Calling our function
myFunction().then();

使用以下命令运行 index.js 文件:

node index.js

输出:

类型:解决 Promsie:承诺{ '解决呼叫一' } 原因:解决呼叫二 类型:解决 Promsie:承诺{ '解决呼叫一' } 原因:解决呼叫三 类型:拒绝 Promsie:承诺{ '解决呼叫一' } 原因:错误:拒绝数据(C:\ Users \ Lenovo \ Downloads \ geeks \ Node JS \ index . JS:27:14) <匿名>(C:\ Users \ Lenovo \ Downloads \ geesforgeks \ Node JS \ index . JS:33:1) at Module。_ 编译(内部/模块/cjs/loader . js:1138:30) at object . module . _ extensions..js(internal/modules/cjs/loader . js:1158:10) at module . load(internal/modules/cjs/loader . js:986:32) at function . module . _ load(internal/modules/cjs/loader . js:879:14) at function . executeuserentrypointas runMain at internal/main/main/

极客们的问候

例 2:

index.js

// Node.js program to demonstrate the  
// Process 'multipleResolves' Event

// Importing process module
const process = require('process');

// Event 'multipleResolves' 
process.on('multipleResolves', (type, promise, reason) => {

   // Displaying the error 
   console.log("Type: ", type);
   console.log("Promsie: ", promise);
   console.log("Reason: ", reason);
});

const myFunction = async () => {
   const data = await new Promise((resolve, reject) => {

      // Calling reject after resolve
      resolve('Single Resolve call');
      reject(new Error('Custom Reason'));
   });
   return data
}

// Calling our function
myFunction().then();

使用以下命令运行 index.js 文件:

node index.js

输出:

类型:拒绝 Promsie: Promise { '单一解析调用} 原因:错误:自定义原因 at data(C:\ Users \ Lenovo \ Downloads \ geesforgeks \ Node JS \ index . JS:19:14) at new Promise() at my function(C:\ Users \ Lenovo \ Downloads \ geesforgeks \ Node JS \ index . JS:16:23) at Object。<匿名>(C:\ Users \ Lenovo \ Downloads \ geesforgeks \ Node JS \ index . JS:25:1) at Module。_ 编译(内部/模块/cjs/loader . js:1138:30) at object . module . _ extensions..js(internal/modules/cjs/loader . js:1158:10) at module . load(internal/modules/cjs/loader . js:986:32) at function . module . _ load(internal/modules/cjs/loader . js:879:14) at function . executeuserentrypointas runMain at internal/main/main

参考:https://nodejs . org/dist/latest-v 16 . x/docs/API/process . html # process _ event _ multipleresolves

---

版权属于：月萌API www.moonapi.com，转载请注明出处

本文链接：https://www.moonapi.com/news/9539.html