已关闭。此问题需要details or clarity。它目前不接受回答。
**希望改进此问题？**通过editing this post添加详细信息并阐明问题。

7天前关闭
Improve this question的
我想在react中改变折线图的最后一段的颜色，我正在使用chartjs库

import React from "react";
import { Line } from "react-chartjs-2";
import "../Styles/charitem.css";
import {
  Chart,
  LinearScale,
  CategoryScale,
  PointElement,
  LineElement,
} from "chart.js";
Chart.register(LinearScale, CategoryScale, PointElement, LineElement);

function ChartItem() {
  const last_element = (ctx, value) => {
    if (ctx.p0DataIndex === 0) {
      return value;
    }
    return undefined;
  };
  const historicalData = {
    labels: Array.from({ length: 7 }, (_, index) => getTimeLabel(index + 9, 0)),
    datasets: [
      {
        label: "Stock Price",
        data: Array.from({ length: 6 }, () => getRandomPrice(100, 250)),
        borderColor: "blue",
        backgroundColor: "rgba(0, 0, 255, 0.2)",
        tension: 0.4,
        segment: {
          borderColor: (ctx) =>
            last_element(ctx, "rgba(0, 0, 255, 0.2)") ||
            down(ctx, "rgba(255,0,0, 1)") ||
            "   rgba(0,128,0,1)",
        },
      },
    ],
  };

  return (
    <div className="chartitem-div">
      <Line data={historicalData} options={options} />
    </div>
  );
}

// Helper function to generate random price between min and max
function getRandomPrice(min, max) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

// Helper function to format time label
function getTimeLabel(hours, minutes) {
  return `${String(hours).padStart(2, "0")}:${String(minutes).padStart(
    2,
    "0"
  )}`;
}

export default ChartItem;

字符串
我可以使用last_element函数中的ctx.p0DataIndex对第一个元素进行修改，如何访问数组的最后一个元素，以便我可以更改其颜色？