I have been stuck for days trying to pull data into my components from a Fetch API JSON result. As a React beginner, this has been a challenge for me and any direction to help me learn and resolve the issue is appreciated. I have the following JSON response copied below followed by my component setup.

My thoughts are that I am not pulling in the correct JSON key values in order or something along those lines.

JSON:

{
  "data": [
    {
      "virusIndex": 2,
      "temperature": 26.5,
      "humidity": 58.6,
      "pm25": 3,
      "tvoc": 234,
      "co2": 435,
      "co": 0,
      "airPressure": 991,
      "ozone": 8.7,
      "no2": 19.4,
      "timestamp": 1646109873
    }
  ],
  "usersettings": {
    "temperature": "°C",
    "temp": "c",
    "humidity": "%",
    "pm25": "µg/m^3",
    "dust": "µg/m^3",
    "tvoc": "ppb",
    "voc": "ppb",
    "co2": "ppm",
    "co": "ppm",
    "airPressure": "mbar",
    "pressure": "mbar",
    "ozone": "ppb",
    "no2": "ppb",
    "pm1": "µg/m^3",
    "pm4": "µg/m^3",
    "pm10": "µg/m^3",
    "ch2o": "ppb",
    "light": "lux",
    "sound": "dBA"
  },
  "count": 104
}

App.js:

class App extends Component {

  constructor(props) {
    super(props);
    this.state = {
      airData: []
    }
   }

componentDidMount(){
var myHeaders = new Headers();
      myHeaders.append("Authorization", "Bearer xxxxxxxxx");

      var urlencoded = new URLSearchParams();
      urlencoded.append("macAddress", "xxxxxxxx");
      urlencoded.append("mode", "minute");

      var requestOptions = {
      method: 'POST',
      headers: myHeaders,
      body: urlencoded,
      redirect: 'follow'
      };

  fetch("MY_API_URL", requestOptions)
   .then(response => response.json())
   .then(res => {
     console.log(res)
     this.setState({
       airData: res.data
     })
   });
  }


  
  render () {
        return (
          <div className="app">
            <Header />
            <div className="spacer"></div>
            <OverallStatus />
            {this.state.airData.map(res => {
                  <div>
                    <div className='qualityFactor'>
                      <h1><img src={iconHumidity} alt="Logo" className="iconSmall" />Humidity {res.humidity}%</h1>
                      <ProgressBar completed={res.humidity}
                      maxCompleted={100} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconAirPressure} alt="Logo" className="iconSmall" />Air Pressure {e.AirPressure} hPa</h1>
                      <ProgressBar completed={e.AirPressure}
                      maxCompleted={1030} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconCarbonDioxide} alt="Logo" className="iconSmall" />Carbon Dioxide {e.CO2} ppm</h1>
                      <ProgressBar completed={e.CO2}
                      maxCompleted={2000} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconVOCs} alt="Logo" className="iconSmall" />Chemicals {e.TVOC} ppb</h1>
                      <ProgressBar completed={e.TVOC}
                      maxCompleted={1000} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconParticulateMatter} alt="Logo" className="iconSmall" />Particles {e.PM25} ug/m3</h1>
                      <ProgressBar completed={e.PM25}
                      maxCompleted={100} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconCarbonMonoxide} alt="Logo" className="iconSmall" />Carbon Monoxide {e.CO} ppm</h1>
                      <ProgressBar completed={e.CO}
                      maxCompleted={100} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconNitrogenDioxide} alt="Logo" className="iconSmall" />Nitrogen Dioxide {e.NO2} ppb</h1>
                      <ProgressBar completed={e.NO2}
                      maxCompleted={200} className="statusBar" />
                    </div>
                    <div className='qualityFactor'>
                      <h1><img src={iconOzone} alt="Logo" className="iconSmall" />Ozone {e.Ozone} ppb</h1>
                      <ProgressBar completed={e.Ozone}
                      maxCompleted={100} className="statusBar" />
                    </div>
                  </div>
              })}
          </div>
        )
    }
  }
  
  

export default App;

CodePudding user response：

Javascript object keys are case sensitive. So e.CO2 is different from e.co2.

Also you havent declared variable 'e' but you are using it. Its supposed to be 'res'

You also missed return statement inside map function.