echarts按需引入

原引入方式，全部引入import * as echarts from 'echarts'
按需引入import echarts from '@/utils/echarts'
打包体积减少0.5M

// 按需引入 ECharts 核心模块
import * as echarts from 'echarts/core';

// 引入柱状图相关的模块
import { BarChart } from 'echarts/charts'; // 只引入 Bar 图表
import {
  TitleComponent,
  TooltipComponent,
  GridComponent,
  LegendComponent,
  DataZoomComponent,
  DatasetComponent
} from 'echarts/components'; // 引入图表需要的组件

import { CanvasRenderer } from 'echarts/renderers'; // 渲染器

// 注册需要的组件
echarts.use([
  BarChart,
  TitleComponent,
  TooltipComponent,
  GridComponent,
  LegendComponent,
  DataZoomComponent ,
  CanvasRenderer,
  DatasetComponent
]);

export default echarts;