echarts折线图的每个折点都显示数值的实现方式

itemStyle : { normal: {label : {show: true}}}

<script type="text/javascript">
var dom = document.getElementById("container");
var myChart = echarts.init(dom);
var app = {};
option = null;

result = eval({{ chart_data | safe }});

option = {
    title: {
        text: result.title,
        x: 'center',
        show : true
    },
    tooltip: {
        formatter: '{b}\n{c}'
     },
    xAxis: {
        type: 'category',
        data: result.feature
    },
    yAxis: {
        type: 'value'
    },
    series: [{
        data: result.data,
        type: 'line',
        // 显示数值
        itemStyle : { normal: {label : {show: true}}}
    }]

};


if (option && typeof option === "object") {
    myChart.setOption(option, true);
}
</script>

//温度、湿度、风速、风向、气压、照度单位
let getUnitType = (type,value) => {
  type = Number(type);
  var unit = '';
  switch (type) {
    case 209033:
      unit = '℃';
      break;
    case 209034:
      unit = '%';
      break;
    case 209035:
      unit = 'm/s';
      break;
    case 209036:
      unit = getWindDirection(value);
      break;
    case 209037:
      unit = 'HPa';
      break;
    case 200088:
      unit = 'Lux';
      break;
  }
  return unit;
};

    tooltip: {
      trigger: 'axis',
      formatter: function (params) {
        var relVal = params[0].name
        for (var i = 0, l = params.length; i < l; i++) {
          relVal += '<br/>' + params[i].marker + params[i].value + getUnitType(pollutionTypeMap1New[pltKey],params[i].value)
        }
        return relVal
      }
    },

    tooltip: {
      trigger: 'axis',
      formatter: function (obj) {
        let arr = obj.map((item, i) => {
          return (
            item.marker +
            item.value +
            '(' +
            getUnitType(pollutionTypeMap1New[pltKey],item.value) +
            ')' +
            '<br>'
          );
        });
        return obj[0].name + '<br>' + arr.join(' ');
      },
    },