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MeG1tsune's questions

Martin Hope
MeG1tsune
Asked: 2025-01-25 03:20:07 +0000 UTC
  • 4

在 expressjs 中，使用中间件层通过类来处理传入的调用 /middlewares/index.js

class Middlewares {
  constructor(options) {
    this.options = options;
  }

  general(req, res, next) {
    console.log(this.options)
  }

  test() {
    console.log(this.options)
  }
}

export default Middlewares;

在app.js

import express from 'express';
import { createServer } from 'http';
import Middlewares from './middlewares/index.js'

const app = express();

const options = {
  whiteListSite: ['http://localhost:81', 'http://localhost:83'],
};

const server = createServer(app);
const middlewares = new Middlewares(options);

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(middlewares.general); //<-- получаю ошибку TypeError: Cannot read properties of undefined (reading 'options')

middlewares.test() //<-- здесь срабатывает все, в консоль выводиться { whiteListSite: [ 'http://localhost:81', 'http://localhost:83' ] }

app.get('/', function(req, res) {
  res.send('hello world');
});

server.listen(8080, () => {
  console.log(`GateWay app listening on port ${8080}`);
});

在服务器操作期间，当触发处理程序时，即对路由发出任何请求时，函数中general都会生成错误TypeError: Cannot read properties of undefined (reading 'options')，但是当我调用 test() 时，一切都正常运行，没有失败

也就是说，类的函数不能从类构造函数中获取变量。这和什么有关？

javascript