通过节点和快递运行服务器时出错

Question

我仍然是后端的新手，但是自昨天以来，每当我尝试运行服务器时，我都面临一个错误。以下是我的代码和错误

 const express = require("express");
const app = express();

PORT = 8443;

app.listen("PORT", () => {
    console.log("Server up and running")
});

这里是我的错误

    events.js:288
      throw er; // Unhandled 'error' event
      ^

Error: listen EACCES: permission denied PORT
←[90m    at Server.setupListenHandle [as _listen2] (net.js:1292:21)←[39m
←[90m    at listenInCluster (net.js:1357:12)←[39m
←[90m    at Server.listen (net.js:1456:5)←[39m
    at Function.listen (C:\Users\AbTorres9\Desktop\YelpCamp\node_modules\←[4mexpress←[24m\lib\application.js:618:24)
    at Object.<anonymous> (C:\Users\AbTorres9\Desktop\YelpCamp\app.js:6:5)
←[90m    at Module._compile (internal/modules/cjs/loader.js:1158:30)←[39m
←[90m    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1178:10)←[39m
←[90m    at Module.load (internal/modules/cjs/loader.js:1002:32)←[39m
←[90m    at Function.Module._load (internal/modules/cjs/loader.js:901:14)←[39m
←[90m    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)←[39m
Emitted 'error' event on Server instance at:
←[90m    at emitErrorNT (net.js:1336:8)←[39m
←[90m    at processTicksAndRejections (internal/process/task_queues.js:84:21)←[39m {
  code: ←[32m'EACCES'←[39m,
  errno: ←[32m'EACCES'←[39m,
  syscall: ←[32m'listen'←[39m,
  address: ←[32m'PORT'←[39m,
  port: ←[33m-1←[39m
}
[nodemon] app crashed - waiting for file changes before starting...

Answer 1

@@ Abhishek，我认为您正在使用哪个端口而该端口已被您的环境阻止，请将该端口允许在防火墙上，或者仅禁用防火墙并再次访问它即可为您工作！

Answer 2

您应该在app.listen()函数中使用variable而不是string。尝试使用类似这样的内容：

app.listen(PORT, () => {
    console.log("Server up and running")
});

Answer 3

[您缺少查看普通JavaScript的东西。就像定义port。并且.listen函数接受端口变量，而不是输入"PORT"的字符串参见工作示例：

const express = require('express');
const app = express();
const port = 8443;

app.listen(port, () => console.log(`Server running on port ${port}!`));

Answer 4

const express = require("express");
const app = express();
const PORT = 8443;
app.listen(PORT, () => {
     console.log("Server up and running")
});

首先有一些错误，您没有初始化PORT，然后在app.listen（）中将PORT作为字符串传递了