echarts 饼图自动高亮展示数据

（1）鼠标不移动上去得时候，饼图自动按照顺序高亮

（2）鼠标移入的时候，取消自动高亮展示，只高亮鼠标选中的那一块

（3）鼠标移出的时候，恢复自动高亮的代码

    var chartDom = document.getElementById('middleLeft1');
    var myChart = echarts.init(chartDom);
    var option = {
        tooltip: {
            trigger: 'item'
        },
        series: [
            {
                name: 'Access From',
                type: 'pie',
                radius: ['50%', '70%'],
                avoidLabelOverlap: false,
                label: {
                    show: false,
                    position: 'center'
                },
                emphasis: {
                    label: {
                        show: true,
                        fontSize: 14,
                        fontWeight: 'bold'
                    }
                },
                labelLine: {
                    show: false
                },
                data: [
                    { value: 1048, name: 'Search Engine' },
                    { value: 735, name: 'Direct' },
                    { value: 580, name: 'Email' },
                    { value: 484, name: 'Union Ads' },
                    { value: 300, name: 'Video Ads' }
                ]
            }
        ]
    };
    option && myChart.setOption(option);
    var bool = true
    var index = 0
    myChart.on('mouseover', (param) => {
        bool = false
        clearInterval((window as any).startCharts)
        myChart.dispatchAction({
            type: 'downplay',
            seriesIndex: 0,
            dataIndex: index
        })
        myChart.dispatchAction({
            type: 'highlight',
            seriesIndex: 0,
            dataIndex: param.dataIndex
        })
        myChart.dispatchAction({
            type: 'showTip',
            seriesIndex: 0,
            dataIndex: param.dataIndex
        })
    })
    function chartHover() {
        var dataLen = option.series[0].data.length
        myChart.dispatchAction({
            type: 'downplay',
            seriesIndex: 0,
            dataIndex: index
        })
        index = (index + 1) % dataLen
        myChart.dispatchAction({
            type: 'highlight',
            seriesIndex: 0,
            dataIndex: index
        })
        myChart.dispatchAction({
            type: 'showTip',
            seriesIndex: 0,
            dataIndex: index
        })
    }
    chartHover();
    (window as any).startCharts = setInterval(chartHover, 2000)
    myChart.on('mouseout', function () {
        if (!bool) {
            (window as any).startCharts = setInterval(chartHover, 2000)
            bool = true
        }
    })