类型错误:未定义不是函数节点JS

TypeError: undefined is not a function Node JS

本文关键字：函数 节点 JS 错误 未定义 类型      更新时间：2023-09-26

我是JavaScript的新手，我正在运行一个非常基本的代码，但遇到了麻烦。代码如下

我的服务.js 

var http = require('http');
var express = require('express');
var app = express();
var gpioControl = require('./GPIOController');
app.get('/pressUp/', function (req, res){
    console.log("Pressed Up");
    gpioControl.upButtonPress();
});
app.get('/pressDown/', function (req, res){
    console.log("Pressed Down");
    gpioControl.downButtonPress();
});
app.listen(3000);
console.log("The server is running on port 3000");

GPIOController.js

var upButtonPress = function ()
{
    console.log ("UP Button has been pressed!");
}
var downButtonPress = function()
{
    console.log ("Down Button has been pressed!");
}

我得到的错误如下： 

TypeError: undefined is not a function
   at C:'Users'mehroz'Desktop'Rasberry Pi Automation'MyService.js:11:14
   at Layer.handle [as handle_request] (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'layer.js:82:5)
   at next (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'route.js:110:13)
   at Route.dispatch (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'route.js:91:3)
   at Layer.handle [as handle_request] (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'layer.js:82:5)
   at C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'index.js:267:22
   at Function.proto.process_params (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'index.js:321:12)
   at next (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'index.js:261:10)
   at expressInit (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'middleware'init.js:23:5)
   at Layer.handle [as handle_request] (C:'Users'mehroz'Desktop'Rasberry Pi Automation'node_modules'express'lib'router'layer.js:82:5)

如果GPIOController.js是一个节点模块（看起来像是这样），它需要使用CommonJS模式。 话虽如此，您应该将 GPIOController 中的 var 声明更改为导出。您的函数名称在这里声明。

所以， var upButtonPress = function（）{} 会变成

exports.upButtonPress = function(){}

然后，它将像您在 MyService.js 中使用它一样工作。

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