如何使用 react-chartjs-2 过滤和更新数据

Question

我在一个项目中使用 React-Chartjs-2，并且在更新我的图表过滤器时遇到了困难。我正在关注以下演示，但这不仅仅是反应版本，而是香草版本。https://www.youtube.com/watch?v=Gc5JF2TUG7o&t=679s @ 16:32 是更新功能更新图表上的过滤日期。我能够获取日期数组的索引，但我的图表没有更新。如何访问和更新 Line 组件中的标签和数据集值？

import React from 'react';
import {Line} from 'react-chartjs-2'

function BarChart() {

    const dates =  ['2021-08-25', '2021-08-26','2021-08-27','2021-08-28', '2021-08-29', '2021-08-30','2021-08-31' ];
    const datapoints =[1,2,4,9,12,15,16]

   

   

    function filterData() {
        const dates2 = [...dates];
        console.log(dates2);
        const startdate =  document.getElementById('startdate');
        const enddate =  document.getElementById('enddate');
        //get the index number in the array 

        const indexstartdate = dates2.indexOf(startdate.value);
        const indexenddate = dates2.indexOf(enddate.value);
        console.log(indexstartdate);
        console.log(indexenddate);

        //slice the array

        const filterDate = dates2.slice(indexstartdate, indexenddate + 1);

        //replace label in the chart
        //HELP HERE!!!
    

        
    }

    return (
        <div>
        <div>
            <Line id='myChart'
            data={{
                labels:dates,

                datasets: [
                    {
                        label: 'Sales',
                        data:datapoints,
                        backgroundColor: [
                            'rgba(255, 99, 132, 0.2)',
                            'rgba(54, 162, 235, 0.2)',
                            'rgba(255, 206, 86, 0.2)',
                            'rgba(75, 192, 192, 0.2)',
                            'rgba(153, 102, 255, 0.2)',
                            'rgba(255, 159, 64, 0.2)'
                        ],
                        borderColor: [
                            'rgba(255, 99, 132, 1)',
                            'rgba(54, 162, 235, 1)',
                            'rgba(255, 206, 86, 1)',
                            'rgba(75, 192, 192, 1)',
                            'rgba(153, 102, 255, 1)',
                            'rgba(255, 159, 64, 1)'
                        ],
                        borderWidth: 1,
                    },
                    
                ],
            }}
            height={400}
            width={400}
            options={{maintainAspectRatio:false,
            scales: {
                yAxes: [
                    {
                        ticks: {
                            beginAtZero: true,
                        }
                    }
                ]
            },

            }}

        
            />
         
        </div>
        <input type='date' onChange={filterData} id='startdate' />
        <input type='date' onChange={filterData}  id='enddate'  />
        </div>
    )
}

export default BarChart

Answer 1

您需要使用 React 状态，以便您的组件重新渲染。这是我的解决方案，希望对您有所帮助。

import React, { useRef, useState } from "react";
import { Line } from "react-chartjs-2";

function BarChart() {
  const initialDates = [
    "2021-08-25",
    "2021-08-26",
    "2021-08-27",
    "2021-08-28",
    "2021-08-29",
    "2021-08-30",
    "2021-08-31",
  ];
  const initialDataPoints = [1, 2, 4, 9, 12, 15, 16];

  const [dates, setDates] = useState(initialDates);
  const [dataPoints, setDataPoints] = useState(initialDataPoints);

  console.log(dates, dataPoints);

  const inputRef1 = useRef();
  const inputRef2 = useRef();

  function filterData() {
    const dates2 = [...dates];
    const dataPoints2 = [...dataPoints];
    
    //slice the array
    let value1 = inputRef1.current.value;
    let value2 = inputRef2.current.value;
    const indexstartdate = dates2.indexOf(value1);
    const indexenddate = dates2.indexOf(value2);
    console.log(indexstartdate);
    console.log(indexenddate);
    //slice the array
    const filterDate = dates2.slice(indexstartdate, indexenddate + 1);
    const filterDataPoints = dataPoints2.slice(
      indexstartdate,
      indexenddate + 1
    );

    console.log(filterDate, filterDataPoints);

    //replace label in the chart
    //HELP HERE!!!

    setDates(filterDate);
    setDataPoints(filterDataPoints);
    console.log(dates, dataPoints);
  }

  return (
    <div>
      <div>
        <Line
          id="myChart"
          data={{
            labels: dates,

            datasets: [
              {
                label: "Sales",
                data: dataPoints,
                backgroundColor: [
                  "rgba(255, 99, 132, 0.2)",
                  "rgba(54, 162, 235, 0.2)",
                  "rgba(255, 206, 86, 0.2)",
                  "rgba(75, 192, 192, 0.2)",
                  "rgba(153, 102, 255, 0.2)",
                  "rgba(255, 159, 64, 0.2)",
                ],
                borderColor: [
                  "rgba(255, 99, 132, 1)",
                  "rgba(54, 162, 235, 1)",
                  "rgba(255, 206, 86, 1)",
                  "rgba(75, 192, 192, 1)",
                  "rgba(153, 102, 255, 1)",
                  "rgba(255, 159, 64, 1)",
                ],
                borderWidth: 1,
              },
            ],
          }}
          height={400}
          width={400}
          options={{
            maintainAspectRatio: false,
            scales: {
              yAxes: [
                {
                  ticks: {
                    beginAtZero: true,
                  },
                },
              ],
            },
          }}
        />
      </div>
      <input type="date" ref={inputRef1} />
      <input type="date" ref={inputRef2} />
      <button onClick={filterData}>Filter</button>
    </div>
  );
}

export default BarChart;