const temperatureCanvasCtx = 
    document.getElementById('temperature-
    chart').getContext('2d')

    const temperatureChartConfig = {
      type: 'line',
      data: {
        labels: [],
        datasets: [{
          data: [],
          backgroundColor: 'rgba(255, 205, 210, 0.5)'
        }]
      },
      options: {
        legend: {
          display: false
        },
        responsive: true,
        maintainAspectRatio: false,
        scales: {
          yAxes: [{
            ticks: {
              suggestedMin: 10,
              suggestedMax: 40
            }
          }]
        }
      }
    }
    const temperatureChart = new Chart(temperatureCanvasCtx, 
    temperatureChartConfig)

    const humidityCanvasCtx = 
    document.getElementById('humidity-
    chart').getContext('2d')

    const humidityChartConfig = {
      type: 'line',
      data: {
        labels: [],
        datasets: [{
          data: [],
          backgroundColor: 'rgba(197, 202, 233, 0.5)'
       }]
      },
      options: {
        legend: {
          display: false
        },
        responsive: true,
        maintainAspectRatio: false,
        scales: {
          yAxes: [{
            ticks: {
              suggestedMin: 30,
              suggestedMax: 90
            }
          }]
        }
      }
    }
    const humidityChart = new Chart(humidityCanvasCtx, 
     humidityChartConfig)

    const pushData = (arr, value, maxLen) => {
      arr.push(value)
      if (arr.length > maxLen) {
        arr.shift()
      }
    }

    const humidityDisplay = 
    document.getElementById('humidity-display')
    const temperatureDisplay =    
    document.getElementById('temperature-display')

    const fetchTemperature = () => {
      fetch('/temperature')
        .then(results => {
          return results.json()
        })
        .then(data => {
          const now = new Date()
          const timeNow = now.getHours() + ':' + 
     now.getMinutes() + ':' + now.getSeconds()
          pushData(temperatureChartConfig.data.labels, 
    timeNow, 10)
          pushData(temperatureChartConfig.data.datasets[0]
    .data, data.value, 10)
          temperatureChart.update()
          temperatureDisplay.innerHTML = '<strong>' + 
    data.value + '</strong>'
        })
    }

    const fetchHumidity = () => {
      fetch('/humidity')
        .then(results => {
          return results.json()
        })
        .then(data => {
          const now = new Date()
          const timeNow = now.getHours() + ':' + 
    now.getMinutes() + ':' + now.getSeconds()
          pushData(humidityChartConfig.data.labels, timeNow,
     10)
          pushData(humidityChartConfig.data.datasets[0].data,
     data.value, 10)
          humidityChart.update()
          humidityDisplay.innerHTML = '<strong>' + data.value  
     + '</strong>'
        })
    }

    setInterval(() => {
      fetchTemperature()
      fetchHumidity()
    }, 2000)

If these files look good to you, run the index.js file using the node and open your browser to see a fully functional dashboard with dynamic animated charts: