承诺在JS中锻炼

Question

我正在通过简短的URL生成器练习来对JS Promise进行培训，但我陷入了困境。控制台将我发送回：结果：未定义。 我需要帮助！

import express from 'express';
import shortUrl from 'node-url-shortener';
const router = express.Router();

router.get('/', (req, res) => {
  res.render('postUrl');
})

router.post('/test', (req, res) => {

  const getShortUrl = () => {
    return new Promise((resolve, reject) => {
      const test = shortUrl.short('https://google.com', (err, url) => {
          return url;
      });
      resolve(test)
    })
  }

  getShortUrl()
    .then((result) => {
      console.log('Resultat : ' + result)
    })
    .catch((err) => {
      console.log('Error : ' + err)
    })

  res.render('getShortUrl');
})

export { router }

Answer 1

只需将result(test)移动到回调内部即可。像这样：

import express from 'express';
import shortUrl from 'node-url-shortener';
const router = express.Router();

router.get('/', (req, res) => {
  res.render('postUrl');
})

router.post('/test', (req, res) => {

  const getShortUrl = () => {
    return new Promise((resolve, reject) => {
      shortUrl.short('https://google.com', (err, url) => {
          resolve(url);
      });
      
    })
  }

  getShortUrl()
    .then((result) => {
      console.log('Resultat : ' + result)
    })
    .catch((err) => {
      console.log('Error : ' + err)
    })

  res.render('getShortUrl');
})

export { router }