【问题标题】:How to integrate charts with js and jQuery?如何将图表与 js 和 jQuery 集成?
【发布时间】:2022-01-20 19:58:22
【问题描述】:

我正在尝试从 API 获取数据并根据从下拉列表中选择的值编辑端点并为其显示相应的图表,我可以将 js、jQuery 和图表集成在一起吗?以下是我尝试过的代码:

async function bruh(){
  $( document ).ready(function() {
  $('select').on('change', async function() {
    this.value = this.value.toLowerCase();
    const apiUrl = 'https://api.covidtracking.com/v1/states/'+this.value+'/daily.json';

  const response = await fetch(apiUrl)
  const barChatData = await response.json()
  console.log(barChatData)
  const positive = barChatData.map((x) => x.positive)
  const date = barChatData.map((x) => x.date)
  positives = positive
  dates = date
  });
})
}
async function dummyChartbruh() {
  await bruh()
  const ctx = document.getElementById('yourChart').getContext('2d');

  const chart = new Chart(ctx, {
      
      type: 'line',
  
      
      data: {
          labels: dates,
          datasets: [{
              label: 'Positive',
              backgroundColor: 'blue',
              borderColor: 'rgb(255, 99, 132)',
              data: positives,
              fill: false
          }
         
        ]
      },
  
    
      options: {
        tooltips: {
          mode: 'index'
        }
      }
  })
  document.getElementById("yourChart").removeAttribute("hidden");
  $('#yourChart').show()
}

dummyChartbruh() 

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BmbxuPwQa2lc/FVzBcNJ7UAyJxM6wuqIj61tLrc4wSX0szH/Ev+nYRRuWlolflfl" crossorigin="anonymous">
  <link rel="stylesheet" href="/styles.css" />
  <title>Covid Data</title>
</head>
<body>
  <div class="card text-center m-5">
  <div class="card-header">
  <h2>Covid Data</h2>
  <select>
    <option value="AL">Alabama</option>
    <option value="AK">Alaska</option>
    <option value="AZ">Arizona</option>
    <option value="AR">Arkansas</option>
    <option value="CA">California</option>
    <option value="CO">Colorado</option>
    <option value="CT">Connecticut</option>
    <option value="DE">Delaware</option>
    <option value="DC">District Of Columbia</option>
    <option value="FL">Florida</option>
    <option value="GA">Georgia</option>
    <option value="HI">Hawaii</option>
    <option value="ID">Idaho</option>
    <option value="IL">Illinois</option>
    <option value="IN">Indiana</option>
    <option value="IA">Iowa</option>
    <option value="KS">Kansas</option>
    <option value="KY">Kentucky</option>
    <option value="LA">Louisiana</option>
    <option value="ME">Maine</option>
    <option value="MD">Maryland</option>
    <option value="MA">Massachusetts</option>
    <option value="MI">Michigan</option>
    <option value="MN">Minnesota</option>
    <option value="MS">Mississippi</option>
    <option value="MO">Missouri</option>
    <option value="MT">Montana</option>
    <option value="NE">Nebraska</option>
    <option value="NV">Nevada</option>
    <option value="NH">New Hampshire</option>
    <option value="NJ">New Jersey</option>
    <option value="NM">New Mexico</option>
    <option value="NY">New York</option>
    <option value="NC">North Carolina</option>
    <option value="ND">North Dakota</option>
    <option value="OH">Ohio</option>
    <option value="OK">Oklahoma</option>
    <option value="OR">Oregon</option>
    <option value="PA">Pennsylvania</option>
    <option value="RI">Rhode Island</option>
    <option value="SC">South Carolina</option>
    <option value="SD">South Dakota</option>
    <option value="TN">Tennessee</option>
    <option value="TX">Texas</option>
    <option value="UT">Utah</option>
    <option value="VT">Vermont</option>
    <option value="VA">Virginia</option>
    <option value="WA">Washington</option>
    <option value="WV">West Virginia</option>
    <option value="WI">Wisconsin</option>
    <option value="WY">Wyoming</option>
</select>   

  </div>
  <canvas id="myChart" ></canvas>
  <canvas id="yourChart" hidden></canvas>
</div>
  <script src="https://cdn.jsdelivr.net/npm/chart.js@2.8.0"></script>
  <script src="https://code.jquery.com/jquery-3.6.0.min.js" integrity="sha256-/xUj+3OJU5yExlq6GSYGSHk7tPXikynS7ogEvDej/m4=" crossorigin="anonymous"></script>
  <script src="app.js"></script>
</body>
</html>

但是,当下拉列表更改时,它不会在图表上显示任何值,我该如何纠正这个问题?

【问题讨论】:

    标签: javascript jquery chart.js


    【解决方案1】:

    您应该将图表分配给一个全局变量,并在每次从下拉列表中选择不同的状态时更新其数据。之后需要调用chart.update()

    有关详细信息,请参阅 Chart.js 文档中的 Updating Charts

    请查看您修改后的代码,看看它是如何工作的。

    $(document).ready(function() {
      $('select').on('change', function() {
        const state = this.value.toLowerCase();
        fetch('https://api.covidtracking.com/v1/states/' + state + '/daily.json')
          .then(response => response.json())
          .then(json => {
            myChart.data.labels = json.map((x) => x.date);
            myChart.data.datasets[0].data = json.map((x) => x.positive);        
            myChart.update();
          });
      });
    });
    
    const myChart = new Chart('myChart', {
      type: 'line',
      data: {
        labels: [],
        datasets: [{
          label: 'Positive',
          backgroundColor: 'blue',
          borderColor: 'rgb(255, 99, 132)',
          data: [],
          fill: false
        }]
      },
      options: {
        tooltips: {
          mode: 'index'
        }
      }
    });
    <!DOCTYPE html>
    <html lang="en">
    
    <head>
      <meta charset="UTF-8">
      <meta http-equiv="X-UA-Compatible" content="IE=edge">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BmbxuPwQa2lc/FVzBcNJ7UAyJxM6wuqIj61tLrc4wSX0szH/Ev+nYRRuWlolflfl" crossorigin="anonymous">
      <link rel="stylesheet" href="/styles.css" />
      <title>Covid Data</title>
    </head>
    
    <body>
      <div class="card text-center m-5">
        <div class="card-header">
          <h2>Covid Data</h2>
          <select>
            <option>Select State...</option>
            <option value="AL">Alabama</option>
            <option value="AK">Alaska</option>
            <option value="AZ">Arizona</option>
            <option value="AR">Arkansas</option>
            <option value="CA">California</option>
            <option value="CO">Colorado</option>
            <option value="CT">Connecticut</option>
            <option value="DE">Delaware</option>
            <option value="DC">District Of Columbia</option>
            <option value="FL">Florida</option>
            <option value="GA">Georgia</option>
            <option value="HI">Hawaii</option>
            <option value="ID">Idaho</option>
            <option value="IL">Illinois</option>
            <option value="IN">Indiana</option>
            <option value="IA">Iowa</option>
            <option value="KS">Kansas</option>
            <option value="KY">Kentucky</option>
            <option value="LA">Louisiana</option>
            <option value="ME">Maine</option>
            <option value="MD">Maryland</option>
            <option value="MA">Massachusetts</option>
            <option value="MI">Michigan</option>
            <option value="MN">Minnesota</option>
            <option value="MS">Mississippi</option>
            <option value="MO">Missouri</option>
            <option value="MT">Montana</option>
            <option value="NE">Nebraska</option>
            <option value="NV">Nevada</option>
            <option value="NH">New Hampshire</option>
            <option value="NJ">New Jersey</option>
            <option value="NM">New Mexico</option>
            <option value="NY">New York</option>
            <option value="NC">North Carolina</option>
            <option value="ND">North Dakota</option>
            <option value="OH">Ohio</option>
            <option value="OK">Oklahoma</option>
            <option value="OR">Oregon</option>
            <option value="PA">Pennsylvania</option>
            <option value="RI">Rhode Island</option>
            <option value="SC">South Carolina</option>
            <option value="SD">South Dakota</option>
            <option value="TN">Tennessee</option>
            <option value="TX">Texas</option>
            <option value="UT">Utah</option>
            <option value="VT">Vermont</option>
            <option value="VA">Virginia</option>
            <option value="WA">Washington</option>
            <option value="WV">West Virginia</option>
            <option value="WI">Wisconsin</option>
            <option value="WY">Wyoming</option>
          </select>
        </div>
        <canvas id="myChart"></canvas>
      </div>
      <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.6.2/chart.min.js"></script>
      <script src="https://code.jquery.com/jquery-3.6.0.min.js" integrity="sha256-/xUj+3OJU5yExlq6GSYGSHk7tPXikynS7ogEvDej/m4=" crossorigin="anonymous"></script>
      <script src="app.js"></script>
    </body>
    
    </html>

    【讨论】:

    • 该死,非常感谢,我是 jQuery 新手,需要学习很多东西,会尝试理解代码,不知何故,后端 js 对我来说似乎比前端更容易
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