javascript 在 nodejs 中传递消息

Question

谁能帮我解决这个问题？每次收到消息我都想把消息从websocket传到串口

var firmata = require('firmata');
var board = new firmata.Board('COM4');

var WebSocketServer = require('ws').Server;
var wss = new WebSocketServer({ port: 8081 });

wss.on('connection', function connection(websocket) {
    websocket.on('message', function incoming(message) {
    board.servoWrite(5, message); //This doesn't work but how do i send?
}

board.on("ready", function() {
  board.servoWrite(5, 0); // this works but i need the message from above which I cant access.

});

Answer 1

您应该在 board 准备好后添加监听器。

board.on("ready", function() {
    wss.on('connection', function connection(websocket) {
        websocket.on('message', function incoming(message) {
            board.servoWrite(5, message);
        });
    });
});

或者声明一个变量，告诉您它是否准备就绪。

var isReady = false;

board.on("ready", function() {
    isReady = true;
});

wss.on('connection', function connection(websocket) {
    websocket.on('message', function incoming(message) {
        if(isReady)
            board.servoWrite(5, message);
    });
});

Answer 2

这不是语法错误..必须添加

board.servoConfig(5, 0, 30);

我是这样在代码中添加的：

var firmata = require('firmata');
var board = new firmata.Board('COM4',function(){

});

var WebSocketServer = require('ws').Server;
var wss = new WebSocketServer({ port: 8081 });

wss.on('connection', function connection(websocket) {
    websocket.on('message', function incoming(message) {
    board.servoConfig(5, 0, 30);
    board.servoWrite(5, message); //This doesn't work but how do i send?
}

board.on("ready", function() {
  board.servoWrite(5, 0); // this works but i need the message from above which I cant access.

});

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