JavaScript类调用函数

Question

我在编程初学者，我试图在JavaScript类，我想从超控功能onConnMessage致电boardCastinit功能，但我收到此错误信息，请在这个问题上需要帮助。

boReferenceError: boardCastInit is not defined

websocket.js

class websocket extends webSocketModel { 

constructor() { 
    let server = new Server(); 
    let mongodb = new mongoDB(); 
    super(server.server); 
} 




onConnMessage(message) { 

    let clients = this.clients; 
    boardCastInit(1); 
} 


boardCastInit(data){ 
     console.log(data) 
    } 


} 

module.exports = websocket; 

websocketModel.js

const ws = require('websocket').server; 

class webSocketModel { 

constructor(httpServer) { 
    if(!httpServer) throw 'Null Http Server'; 
    this.websocket = new ws({ httpServer: httpServer, autoAcceptConnections: false }); 
    this.websocket.on('request', this.onConnOpen.bind(this)); 
} 


onConnOpen(request) { 
    var connection = request.accept('echo-protocol', request.origin); 
    console.log('Connection Accepted'); 

    connection.on('message', this.onConnMessage); 
    connection.on('close', this.onConnClose); 
} 

onConnMessage(message) { 
    if (message.type === 'utf8') { 
     console.log(message.utf8Data); 
    } else if (message.type == 'binary') { 
     console.log(message.binaryData.length + 'bytes'); 
    } 
} 

onConnClose(reasonCode, description) { 
    console.log('Connection Closed'); 
} 
} 

module.exports = webSocketModel; 

Answer 1

只是改变boardCastInit(1)到this.boardCastInit(1)

onConnMessage(message) { 

    let clients = this.clients; 
    this.boardCastInit(1); 
} 

Answer 2

你应该从类调用它参考：

class websocket extends webSocketModel { 

    constructor() { 
     let server = new Server(); 
     let mongodb = new mongoDB(); 
     super(server.server); 
    } 

    onConnMessage(message) { 
     let clients = this.clients; 
     this.boardCastInit(1); 
    } 


    boardCastInit(data){ 
     console.log(data) 
    } 

} 

module.exports = websocket; 

Answer 3

你错过了这个（应该this.boardCastInit（1））。

Answer 4

这可能是一个有约束力的问题。也许你想使用箭头功能上，而不是你的onConnMessage方法：

onConnMessage = (message) => { 
 
    let clients = this.clients; 
 
    this.boardCastInit(1); 
 
}

这将确保this指websocket类定义了boardCastInit方法。

Answer 5

尝试在这样的构造函数中绑定boardCastInit()函数。

constructor() { 
    let server = new Server(); 
    let mongodb = new mongoDB(); 
    super(server.server); 
    this.boardCastInit = this.boardCastInit.bind(this); 
} 

然后从this参考调用它。

onConnMessage(message) { 
    let clients = this.clients; 
    this.boardCastInit(1); 
}