Question

我正在使用Arduino和raspberry pi构建IoT应用程序。有一项要求是从Arduino读取串行输出。读书是由覆盆子完成的。为此，我正在使用节点串行端口模块。

读取该串行输出时，必须使用一个条件。我只需要包含整数值的那一行，因此我使用了以下代码行。

picture: in here you can see the integer contained line.since this is a loop you can see several lines.I need read that line once for a loop

var sp = new serialport("/dev/ttyACM0", { //for serial communication with arduino 
    //baudrate: 9600,  
    baudRate: 9600,
// we are using UNO so baudrate is 9600, you might need to change according to your model
 //parser: serialport.parsers.readline("\n")
 parser: new Readline("\r\n") 

    if(data === parseInt(data,10)){

        dataTemp = data;


    }


});

如您所见，我使用if条件检查该行是否为整数。但是当我使用腻子执行此操作时，控制台会向我回复以下内容：

picture:putty output

/home/pi/indigo-parking.js:24
        if(data === parseInt(data,10)){
        ^^

SyntaxError: Unexpected token if

所以我想知道有人能帮助我解决这个问题。如果您有任何想法/解决方案，请足够与我分享。（我在下面提供了完整的代码...您可以参考以获得更好的主意）

树莓的完整代码：

//indigo parking data transfer
var webSocketUrl = "wss://api.artik.cloud/v1.1/websocket?ack=true";
var device_id = "861b8f68ff30439288d755b5e7a74374"; // Indigo parking DEVICE ID
var device_token = "0f8681a1bd624624b6d4841358f323c2"; //Indigo parking DEVICE TOKEN
// import websocket module
var WebSocket = require('ws');
var isWebSocketReady = false;
var data="";
var dataTemp="";
var ws = null;
// import serialport module
var serialport = require("serialport");
var SerialPort = serialport.SerialPort;
var Readline = serialport.parsers.Readline
//const port = new SerialPort('/dev/tty-usbserial1')

var sp = new serialport("/dev/ttyACM0", { //for serial communication with arduino 
    //baudrate: 9600,  
    baudRate: 9600,
// we are using UNO so baudrate is 9600, you might need to change according to your model
 //parser: serialport.parsers.readline("\n")
 parser: new Readline("\r\n") 

    if(data === parseInt(data,10)){

        dataTemp = data;


    }


});


var parking_state=0;// variable to check for parking state_gate
// this is for demo purpose only


/**
 * Gets the current time in millis
 */
function getTimeMillis(){
    return parseInt(Date.now().toString());
}

/**
 * Create a /websocket connection and setup GPIO pin
 */
function start() {
    //Create the WebSocket connection
    isWebSocketReady = false;
    ws = new WebSocket(webSocketUrl);
    ws.on('open', function() {
        console.log("WebSocket connection is open ....");
    // after creating connection you have to register with your Authorization information
        register();
    });
    ws.on('message', function(dataTemp) {
      //this loop is called whenever the client sends some message
         handleRcvMsg(dataTemp); //data is received to the function handleRcvMsg()
    });
    ws.on('close', function() {
        console.log("WebSocket connection is closed ....");

    });      

}

/**
 * Sends a register message to /websocket endpoint
 */
//Client will only work when device gets registered from here
function register(){
    console.log("Registering device on the WebSocket connection");
    try{
        var registerMessage = '{"type":"register", "sdid":"'+device_id+'", "Authorization":"bearer '+device_token+'", "cid":"'+getTimeMillis()+'"}';
        console.log('Sending register message ' + registerMessage + '\n');
        ws.send(registerMessage, {mask: true});
        isWebSocketReady = true;
    }
    catch (e) {
        console.error('Failed to register messages. Error in registering message: ' + e.toString());
    }    
}


//data after receiving is sent here for processing
function handleRcvMsg(msg){
    var msgObj = JSON.parse(msg);
    if (msgObj.type != "action") return; //Early return;

    var actions = msgObj.dataTemp.actions;
    var actionName = actions[0].name; //assume that there is only one action in actions
    console.log("The received action is " + actionName);

    //you must know your registered actions in order to perform accordinlgy
    // we will not receive any action in our case
    if (actionName.toLowerCase() == "parking_state") 
    { 
       // your code here 
    }
    else {
         //this loop executes if some unregistered action is received
         //so you must register every action in cloud
        console.log('Do nothing since receiving unrecognized action ' + actionName);
        return;
    }

}



/**
 * Send one message to ARTIK Cloud
 */
//This function is responsible for sending commands to cloud
function sendStateToArtikCloud(parking){
    try{
        ts = ', "ts": '+getTimeMillis();
        var dataTemp = {
            "indigolot": parking
//setting the parking value from argument to our cloud variable "parking"
//we will get the value from arduino
            };
        var payload = '{"sdid":"'+device_id+'"'+ts+', "data": '+JSON.stringify(dataTemp)+', "cid":"'+getTimeMillis()+'"}';
        console.log('Sending payload ' + payload + '\n');
        ws.send(payload, {mask: true});
    } catch (e) {
        console.error('Error in sending a message: ' + e.toString() +'\n');
    }    
}



function exitClosePins() {

        console.log('Exit and destroy all pins!');
        process.exit();

}


start();
//exectes every time when data is received from arduino (30sec programmed delay from arduino)
sp.on("open", function () {
    sp.on('data', function(dataTemp) {

            console.log("Serial port received data:" + dataTemp);
            //sendStateToArtikCloud(data);//parking data to artik cloud
            sendStateToArtikCloud(dataTemp);

    });
});


process.on('SIGINT', exitClosePins);

Answer 1

不是很明显的语法错误吗？

var sp = new serialport("/dev/ttyACM0", {
    baudRate: 9600,
    parser: new Readline("\r\n") 
    if(data === parseInt(data,10)){//// this line////
        dataTemp = data;
    }
});

serialport构造函数接受一个对象作为第二个参数。您正在对象内部编写if子句。

不知道串行端口，但是如果解析器接受函数，则可以在其周围包装一个函数。或也许使用一个iife

parser: (function(){
    let data = new Readline("\r\n") 
    if(data === parseInt(data,10)){
        dataTemp = data;
        return dataTemp;
    })();

或者类似的东西

尝试在树莓派上运行javascript时出现SyntaxError

1 个答案: