ECharts For Vue  

npm i -S echarts-for-vue

import { createApp, h } from 'vue';
import { plugin } from 'echarts-for-vue';
import * as echarts from 'echarts';

const app = createApp({ /*...*/ });
app.use(plugin, { echarts, h });                        // use as a plugin

<template>
    <ECharts ref="chart" :option="option" />
</template>

<script>
    import { createComponent } from 'echarts-for-vue';
    import * as echarts from 'echarts';
    import { h } from 'vue';

    export default {
        components: {
            ECharts: createComponent({ echarts, h }),   // use as a component
        },
        data: () => ({
            option: { /*...*/ },
        }),
        methods: {
            doSomething() {
                this.$refs.chart.inst.getWidth();       // call the method of ECharts instance
            },
        },
    }
</script>

import Vue from 'vue';
import { plugin } from 'echarts-for-vue';
import * as echarts from 'echarts';

Vue.use(plugin, { echarts });                           // use as a plugin

<template>
    <ECharts ref="chart" :option="option" />
</template>

<script>
    import { createComponent } from 'echarts-for-vue';
    import * as echarts from 'echarts';

    export default {
        components: {
            ECharts: createComponent({ echarts }),      // use as a component
        },
        data: () => ({
            option: { /*...*/ },
        }),
        methods: {
            doSomething() {
                this.$refs.chart.inst.getWidth();       // call the method of ECharts instance
            },
        },
    }
</script>