handle exception the right way with async/await && promise && express

test.js

//测试 express && async 的异常处理

import express from 'express';

let router = express.Router();

function badass() {
    return new Promise(async(resolve, reject)=> {
        console.log('before throw error');

        throw new Error('test');

        console.log('after throw error');
    });
}

function mistake() {
    return new Promise(async(resolve, reject)=> {
        console.log('before throw error');

        return reject(new Error('test')); // reject 并不会中断执行

        console.log('after throw error');
    });
}


function weired_mistake() {
    return new Promise(async(resolve, reject)=> {
        console.log('before throw error');

        resolve(new Error('test'));

        console.log('after throw error');
    });
}

function decent_mistake() {
    return new Promise(async (resolve, reject)=>{

       try {
           console.log(resolve.toString());
           console.log(reject.toString());

           console.log('before throw error');

           throw new Error('test');

           console.log('after throw error');
       } catch (e) {
           console.error('catch error');

           return resolve(e);
       }
    });
}

// 僵死, 之后进程自动重启
//before await
//before throw error
router.route('/')
    .get(async (req, res, next) => {
        console.log('before await');

        let data = await badass();

        console.log('after await', data);

        res.end();
    });


// 僵死
//before await
//before throw error
router.route('/catch')
    .get(async(req, res, next)=> {
        try {
            console.log('before catch await');

            let data = await badass();

            console.log('after await', data);

        } catch (e) {
            console.error(e);
        } finally {
            res.end();
        }
    });


// 僵死
//before await
//before throw error
router.route('/mistake')
    .get(async (req, res, next) => {
        console.log('before await');

        let data = await mistake();

        console.log('after await', data);

        res.end('done');
    });


// 不是很正常, 因为 mistake
//before catch await
//before throw error
//after throw error
//    [Error: test]
router.route('/mistake/catch')
    .get(async(req, res, next)=> {
        try {
            console.log('before catch await');

            let data = await mistake();

            console.log('after await', data);

            res.end();
        } catch (e) {
            console.error(e);
        } finally {
            res.end('done');
        }
    });

// 正常, 但是无用, await 中出现了异常, 但是并没有中断接口的执行
//before await
//before throw error
//after throw error
//after await [Error: test]
router.route('/weired_mistake')
    .get(async (req, res, next) => {
        console.log('before await');

        let data = await weired_mistake();

        console.log('after await', data);

        res.end('done');
    });


// 可以处理真正的异常
//before await
//before throw error
//catch error
//after await [Error: test]
router.route('/decent_mistake')
    .get(async (req, res, next) => {
        console.log('before await');

        let data = await decent_mistake();

        console.log('after await', data);

        res.end('done');
    });

module.exports = router;