如何优雅地在Node应用中进行错误异常处理

function test() {
 try {
 throw new Error("error");
 } catch(err) {
 console.log("some error happened:");
 }
}

 
test()

const fs = require('fs');

function read() {
 fs.readFile("/some/file/does-not-exist", (err, data) => {
 if(err) {
  throw new Error("file not exist");
 }
 console.log(data);
 });
}

read();

fs.mkdir("./temp").then(() => {
 fs.writeFile("./temp/foobar.txt", "hello");
}).catch(err => {
 console.log(err)
});

async function one() {
 await two();
}

async function two() {
 await "hello";
 throw new Error("error");
}

async function test() {
 try {
 await one();
 } catch(error) {
 console.log(error);
 }
}

test();

const database = require("database");

function promiseGet(query) {
 return new Promise((resolve, reject) => {
  database.get(query, (err, result) => {
   if (err) {
    reject(err);
   } else {
    resolve(result);
   }
  })
 })
}

async function main() {
 await promiseGet("foo");
}

main();

class ApplicationError extends Error {
 constructor(message, options = {}) {
 assert(typeof message === 'string');
 assert(typeof options === 'object');
 assert(options !== null);
 super(message);

 // Attach relevant information to the error instance
 // (e.g., the username).
 for (const [key, value] of Object.entries(options)) {
  this[key] = value;
 }
 }

 get name() {
 return this.constructor.name;
 }
}

class UserFacingError extends ApplicationError {
 constructor(message, options = {}) {
 super(message, options);
 }
}

class BadRequestError extends UserFacingError {
 get statusCode() {
 return 400
 }
}

class NotFoundError extends UserFacingError {
 get statusCode() {
 return 404
 }
}

class DatabaseError extends ApplicationError {
 get toString() {
 return "Errored happend in query: " + this.query + "\n" + this.message;
 }
}

// 使用的话
throw new DatabaseError("Other message", {
 query: query
});

app.use('/user', (req, res, next) => {
 const data = await database.getData(req.params.userId);
 if (!data) {
 throw new NotFoundError("User not found")
 }
 
 // do other thing
});

// 错误处理中间件
app.use(async (err, req, res, next) => {
 if (err instanceof UserFacingError) {
 res.sendStatus(err.statusCode);
 // or
 res.status(err.statusCode).send(err.errorCode)
 } else {
 res.sendStatus(500)
 }
 
 // 记录日志
 await logger.logError(err, 'parameter:', req.params, 'User Data:', req.user);
 // 发送邮件
 await sendMailToAdminIfCritical();
})

// 发生网络错误的时候隔200ms,重试3次
function query(queryStr, token, repeatTime = 0, delay = 200) {
 try {
 await db.query(queryStr);
 } catch (err) {
 if (err instanceof NetworkError && repeatTime < 3) {
  query(queryStr, token, repeatTime + 1, delay);
 }
 
 throw err;
 }
}

process.on('unhandledRejection', error => {

 console.error('unhandledRejection', error);
 // To exit with a 'failure' code
 process.exit(1);
});

node app.js --unhandled-rejections