TypeError：undefined不是函数Node JS

Question

我是JavaScript的新手，我正在运行一个非常基本的代码，但遇到问题。代码如下所示

MyService.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!"); 
} 

我得到的错误是如下：

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) 

Answer 1

如果GPIOController。 js是节点模块le（它看起来就是这样），它需要使用CommonJS模式。话虽如此，你应该将GPIOController中的var声明更改为导出。 你的功能名称在这里声明。

所以，VAR upButtonPress =函数（）{}将成为

exports.upButtonPress = function(){} 

然后，它将为您在MyService.js使用它。