将 JSON 响应对象添加到 React Native 中的 useState 数组/字典

Question

I have a function getSensors which gets all of the existing sensors first and then calls getDataForSpecificSensor(sensor)

const [sensorData, setSensorData] = useState([])

function getSensors() {
        tensor.get('Sensorsid')
            .then(function (response) {
                setSensors(response.data)
                for (i = 0; i < sensors.length; i++) {
                    getSensorDataForSpecificSensor(sensors[i])
                }
            })
    }

function getSensorDataForSpecificSensor(sensorsid) {
        tensor.get("Sensorperiod/" + sensorsid + "/2")
            .then(function (response) {
                //Use setSensorData() to set the response to the matching sid(deviceid), create new if it doesn't exist
            })
            .catch(function (error) {
                console.log(error)
            })
    }

The JSON returned by getDataForSpecificSensor looks like this:

[{"id":2568,"sid":"arduino01","temperatur":32.06,"zeit":"2021-12-26T20:52:39.981682"}]

My question is: Should I use a two dimensional array for this? A dictionary? If either how do I add the response only to the matching sid to sensorData and create a new one if it doesn't exist? useState in React native makes it a bit more difficult for me to grasp.

Should work something like this:

Answer 1

One way to manage this data is to have an object whose keys are the sid and the values are array of data points for that sid like this:

{
  arduino01: [
    {temperatur: 1, "zeit":"2021-12-26T20:52:39.981682"}, 
    {temperatur: 2, "zeit":"2021-12-26T20:52:39.981682"}
  ],
  arduino02: [{temperatur: 3, "zeit":"2021-12-26T20:52:39.981682"}]
}

And you could update the object like this:

const [sensorData, setSensorData] = useState({});

...

function getSensorDataForSpecificSensor(sensorsid) {
  tensor.get("Sensorperiod/" + sensorsid + "/2").then(function (response) {
    const key = response.data.sid;
    const newData = response.data.data;

    if(!sensorData[key]) {
      // when the sid doesn't exist yet, create new key value pair
      setSensorData(previous => {
        previous.key = [newData];
        return {...previous};
      });
    } else {
      //when the sid exist already, add the newData to the existing data points
      const newValueForKey = [...sensorData.key, newData];
      setSensorData(previous => {
        previous.key = newValueForKey;
        return {...previous};
      })
    }
  }).catch(function (error) {
      console.log(error)
  })
}

I think arranging data like this does make it a little easier to update. If you want to loop through all of the key value pairs, you could use something like Object.entries() to transform the object into an array.