How to clear special characters from the expression Document.getElementById("Humidity"). value;

Question

I’m riding my own payload but he’s coming like this:

{
    "mode": "sync",
    "messageType": "57cd765743f3f9c473d5",
    "messages": [{
        "Humidity": "99.1",
        "Temperature": "99.2",
        "Brightness": "99.3",
        "Timestamp": "1999999999"
    }]
}

When you should go like this:

{
    "mode": "sync",
    "messageType": "57cd765743f3f9c473d5",
    "messages": [{
        "Humidity": 25.7,
        "Temperature": 21.5,
        "Brightness": 13.0,
        "timestamp": 1413100000
    }]
}

Code:

//Creates a new Messaging.Message Object and sends it to the HiveMQ MQTT Broker
var publish = function(payload, topic, qos) {

    mensagem.Humidity = document.getElementById("humidity").value;
    mensagem.Temperature = document.getElementById("temperature").value;
    mensagem.Brightness = document.getElementById("brightness").value;
    mensagem.Timestamp = document.getElementById("timestamp").value;

    pl.messages = new Array();
    pl.messages[0] = mensagem;

    console.log(JSON.stringify(pl));

    //Send your message (also possible to serialize it as JSON or protobuf or just use a string, no limitations)
    var message = new Messaging.Message(payload);
    message.destinationName = topic;
    message.qos = 2;

    //message.retained = true;
    client.send(message);
}

How do I clean up those "" leftover in mine payload?

Answer 1

The attribute value of an HTML element is always string.

All you need to do is convert to float or int according to your need.

Example:

var input_int = document.getElementById('int').value;
var input_float = document.getElementById('float').value;
var input_string = document.getElementById('string').value;

// Todos são strings
console.log({
  "input_int": input_int,
  "input_float": input_float,
  "input_string": input_string
});

// Converte o que é número para o tipo correto
input_int = parseInt(input_int, 10);
input_float = parseFloat(input_float);

// Com os tipos corretos, o JSON é criado corretamente
console.log({
  "input_int": input_int,
  "input_float": input_float,
  "input_string": input_string
});

<input type="number" id="int" value="5" />
<br>
<input type="number" id="float" value="2.5" />
<br>
<input type="text" id="string" value="string" />

Answer 2

HTML field values are strings. The resulting JSON to call JSON.stringify with these values will actually be a JSON whose values will have double quotes.

If you do not want your JSON to contain strings, you must convert its values to the numeric type of Javascript. In your case, the timestamp is integer, so you can use the function parseInt javascript:

mensagem.Timestamp = parseInt(document.getElementById("timestamp").value);

The other values are not integer. For them you use the function parseFloat:

mensagem.Humidity = parseFloat(document.getElementById("humidity").value);
mensagem.Temperature = parseFloat(document.getElementById("temperature").value);
mensagem.Brightness = parseFloat(document.getElementById("brightness").value);