Express.js控制器内错误处理：异步函数未终止致服务器崩溃

我实现了用户注册API接口/register，该路由处理函数为异步函数，需在AuthController中调用异步函数进行密码哈希，路由代码如下：

authRouter.post('/register', async (req: Request, res: Response, next: NextFunction) => {
    const { username, password } = req.body;
    
    const hashedPassword = await AuthController.hashPassword(password, next);

    // 其他操作

在AuthController的hashPassword函数中，我通过抛出错误测试错误处理逻辑，代码如下：

const hashPassword = async (password: string, next: NextFunction): Promise<void> => {
    try {
        throw new Error('test error');
        //return await bcrypt.hash(password, 10);
    } catch(err) {
        next(err);
    }
} 

但测试API时服务器完全崩溃，日志如下：

[1] Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[1]     at new NodeError (node:internal/errors:400:5)
[1]     at ServerResponse.setHeader (node:_http_outgoing:663:11)
[1]     at ServerResponse.header (C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\node_modules\express\lib\response.js:794:10)
[1]     at ServerResponse.send (C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\node_modules\express\lib\response.js:174:12)
[1]     at ServerResponse.json (C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\node_modules\express\lib\response.js:278:15)
[1]     at ServerResponse.send (C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\node_modules\express\lib\response.js:162:21)
[1]     at C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\dist\src\routes\auth\auth.js:72:25
[1]     at Generator.next (<anonymous>)
[1]     at fulfilled (C:\Users\renet\Desktop\git\rapidhcm-monorepo\api\dist\src\routes\auth\auth.js:28:58)
[1]     at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
[1]   code: 'ERR_HTTP_HEADERS_SENT'
[1] }
[1]
[1] Node.js v18.13.0

我推测错误原因是：hashPassword函数触发catch后并未终止执行，路由处理函数继续执行后续的"其他操作"代码，而该部分最终尝试发送响应，导致重复发送响应头。

我可以在路由函数中添加try/catch块，但不想这么做，原因有二：

• 我认为这是不良设计——将try/catch块放在独立函数中更便于代码阅读；
• 由于无法读取try/catch块外部的变量，不得不为整个函数添加一个大的try/catch块。

补充说明：以下是"其他操作"的代码细节：

try {
        await User.create({ username, password: hashedPassword ?? 's' });
        res.send({ username, password, hashedPassword });
    } catch (error) {
        console.error('Something went wrong when adding a new user', error);
        res.status(400).send({
            message: 'User already exists in the database',
        });
    }

内容的提问来源于stack exchange，提问作者Damian Kowalski