如何在 Node Js 中显示 api 结果时修复“ReferenceError: $ is not defined”

Question

I am trying to get the result from an api and show it in an html page. I have included body-parser and app.use method.But as soon as i enter value and submit,i am getting the error: ReferenceError: flightStatus is not defined. The api usage is successfull, I am a beginner, so please pardon if it is a fstupid question. Any help is greatly appreciated: Here is my server code :

app.post("/iatatracker", function (req, res) {

    console.log(req);

    
    let apiKey = 'somekey';
    let iataQuery = req.body.iatacode; 
    let airlineIcaoQuery = req.body.flighticao;
    let url = `http://api.aviationstack.com/v1/flights?access_key=${apiKey}&airline_icao=${airlineIcaoQuery}&flight_iata=${iataQuery}`;
    http.get(url, function (response) {
    
        response.on('data', function (data) {
            let flightData = JSON.parse(data);
            let flightStatus = flightData.data.flight_status;
            console.log(flightStatus);
    
    
        });
    })
    
    res.write(` The ${flightStatus}`);
}

Here is my html form code

 <form class="form" name="iata" action="/iatatracker" method="POST"  onsubmit="validateForm()">

        <label for="iatacode"> Enter IATA Code : (for example : 6E881) </label>
        <input type="text" name="iatacode" id="iatacode">

        <label for="flighticao"> Enter Flight ICAO Code : (for eg: igo for Indigo Airlines) </label>
        <input type="text" name="flighticao" id="flighticao">

        <button class="btn" type="submit"> Check Flight History </button>

Thank you so much in advance!!

Answer 1

So from your code I can get is you are trying to access flightStatus variable out of its scope.

You can use res.write(` The ${flightStatus}`); inside your response.on function's callback function as below.

http.get(url, function (response) {

        response.on('data', function (data) {
            let flightData = JSON.parse(data);
            let flightStatus = flightData.data.flight_status;
            console.log(flightStatus);
            res.write(` The ${flightStatus}`);

        });
    });

Solution 2: Taking reference from jfriend00 's comment.

You can create a function to pass the data from response.on 's callback function as below:

http.get(url, function (response) {

        response.on('data', function (data) {
            let flightData = JSON.parse(data);
            let flightStatus = flightData.data.flight_status;
            console.log(flightStatus);
            sendResponse(flightStatus);

        });
    });

function sendResponse(flightStatus) {
    res.write(` The ${flightStatus}`);
}

Let me know in comment if this solves your issue.