Vue-echarts error: was not found in vue-demi [How to Solve]

Was not found in Vue Demi

version problem. Vue-echarts6.0.0 is vue3. When it is introduced into vue2, an alarm will appear
you can go back to version 4.0.2

npm install [email protected] -S

Vue-echarts4.0.2 corresponds to echarts4, so echats also returns the version

npm install [email protected] -S

Prompt personal version record

"dependencies": {
    "core-js": "^3.6.5",
    "echarts": "^4.9.0",
    "vue": "^2.6.11",
    "vue-echarts": "^4.0.2"
  },

Introduce in main.js

import ECharts from 'vue-echarts'
// import * as echarts from 'echarts' //Global introduction
// Vue.prototype.$echats = echarts;
import 'echarts/lib/chart/line' // On-demand introduction
Vue.component('chart', ECharts)