'uncaughtException' 事件

• err <Error> 未捕获的异常。
• origin <string> 指示异常是源自未处理的拒绝还是源自同步错误。 可以是 'uncaughtException' 或 'unhandledRejection'。 后者用于在基于 Promise 的异步上下文中发生异常（或者如果 Promise 被拒绝）并且 --unhandled-rejections 标志设置为 strict 或 throw（这是默认值）并且拒绝未被处理，或者当拒绝发生在命令行入口点的 ES 模块静态加载阶段。

当未捕获的 JavaScript 异常一直冒泡回到事件循环时，则会触发 'uncaughtException' 事件。 默认情况下，Node.js 通过将堆栈跟踪打印到 stderr 并以代码 1 退出，覆盖任何先前设置的 process.exitCode 来处理此类异常。 为 'uncaughtException' 事件添加句柄会覆盖此默认行为。 或者，更改 'uncaughtException' 处理程序中的 process.exitCode，这将导致进程以提供的退出码退出。 否则，在存在此类句柄的情况下，进程将以 0 退出。

import process from 'node:process';

process.on('uncaughtException', (err, origin) => {
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}`,
  );
});

setTimeout(() => {
  console.log('This will still run.');
}, 500);

// 故意引发异常，但不捕获。
nonexistentFunc();
console.log('This will not run.');const process = require('node:process');

process.on('uncaughtException', (err, origin) => {
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}`,
  );
});

setTimeout(() => {
  console.log('This will still run.');
}, 500);

// 故意引发异常，但不捕获。
nonexistentFunc();
console.log('This will not run.');

通过安装 'uncaughtExceptionMonitor' 监听器，可以在不覆盖退出进程的默认行为的情况下监视 'uncaughtException' 事件。

• err <Error> The uncaught exception.
• origin <string> Indicates if the exception originates from an unhandled rejection or from a synchronous error. Can either be 'uncaughtException' or 'unhandledRejection'. The latter is used when an exception happens in a Promise based async context (or if a Promise is rejected) and --unhandled-rejections flag set to strict or throw (which is the default) and the rejection is not handled, or when a rejection happens during the command line entry point's ES module static loading phase.

The 'uncaughtException' event is emitted when an uncaught JavaScript exception bubbles all the way back to the event loop. By default, Node.js handles such exceptions by printing the stack trace to stderr and exiting with code 1, overriding any previously set process.exitCode. Adding a handler for the 'uncaughtException' event overrides this default behavior. Alternatively, change the process.exitCode in the 'uncaughtException' handler which will result in the process exiting with the provided exit code. Otherwise, in the presence of such handler the process will exit with 0.

import process from 'node:process';

process.on('uncaughtException', (err, origin) => {
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}`,
  );
});

setTimeout(() => {
  console.log('This will still run.');
}, 500);

// Intentionally cause an exception, but don't catch it.
nonexistentFunc();
console.log('This will not run.');const process = require('node:process');

process.on('uncaughtException', (err, origin) => {
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}`,
  );
});

setTimeout(() => {
  console.log('This will still run.');
}, 500);

// Intentionally cause an exception, but don't catch it.
nonexistentFunc();
console.log('This will not run.');

It is possible to monitor 'uncaughtException' events without overriding the default behavior to exit the process by installing a 'uncaughtExceptionMonitor' listener.