Node.js proces 'beforeExit'事件用法及代碼示例

事件：'beforeExit'

'beforeExit' 事件在 Node.js 清空其事件循環並且沒有其他工作要安排時發出。通常情況下，Node.js 進程會在沒有安排工作時退出，但在'beforeExit' 事件上注冊的偵聽器可以進行異步調用，從而使 Node.js 進程繼續。

使用作為唯一參數傳遞的 process.exitCode 的值調用偵聽器回調函數。

'beforeExit' 事件不會針對導致顯式終止的條件發出，例如調用 process.exit() 或未捕獲的異常。

'beforeExit' 不應用作'exit' 事件的替代，除非打算安排額外的工作。

import process from 'node:process';

process.on('beforeExit', (code) => {
  console.log('Process beforeExit event with code: ', code);
});

process.on('exit', (code) => {
  console.log('Process exit event with code: ', code);
});

console.log('This message is displayed first.');

// Prints:
// This message is displayed first.
// Process beforeExit event with code: 0
// Process exit event with code: 0const process = require('node:process');

process.on('beforeExit', (code) => {
  console.log('Process beforeExit event with code: ', code);
});

process.on('exit', (code) => {
  console.log('Process exit event with code: ', code);
});

console.log('This message is displayed first.');

// Prints:
// This message is displayed first.
// Process beforeExit event with code: 0
// Process exit event with code: 0