Echart line chart: when multiple lines have the same name, the legend is still displayed

By default

option = {
    
  title: {
    
    text: 'Stacked Line'
  },
  tooltip: {
    
    trigger: 'axis'
  },
  legend: {
    
    show: true
    // data: ['Email', 'Union Ads', 'Video Ads', 'Direct', 'Search Engine']
  },
  grid: {
    
    left: '3%',
    right: '4%',
    bottom: '3%',
    containLabel: true
  },
  toolbox: {
    
    feature: {
    
      saveAsImage: {
    }
    }
  },
  xAxis: {
    
    type: 'category',
    boundaryGap: false,
    data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  },
  yAxis: {
    
    type: 'value'
  },
  series: [
    {
    
      name: 'Email',
      type: 'line',
      stack: 'Total',
      data: [120, 132, 101, 134, 90, 230, 210]
    },
    {
    
      name: 'Union Ads',
      type: 'line',
      stack: 'Total',
      data: [220, 182, 191, 234, 290, 330, 310]
    },
    {
    
      name: 'Video Ads',
      type: 'line',
      stack: 'Total',
      data: [150, 232, 201, 154, 190, 330, 410]
    },
    {
    
      name: 'Direct',
      type: 'line',
      stack: 'Total',
      data: [320, 332, 301, 334, 390, 330, 320]
    },
    {
    
      name: 'Search Engine',
      type: 'line',
      stack: 'Total',
      data: [820, 932, 901, 934, 1290, 1330, 1320]
    }
  ]
};

When the polyline has the same name , Only one... Will be displayed if the legend is the same

option = {
    
  title: {
    
    text: 'Stacked Line'
  },
  tooltip: {
    
    trigger: 'axis'
  },
  legend: {
    
    show: true
    // data: ['Email', 'Union Ads', 'Video Ads', 'Direct', 'Search Engine']
  },
  grid: {
    
    left: '3%',
    right: '4%',
    bottom: '3%',
    containLabel: true
  },
  toolbox: {
    
    feature: {
    
      saveAsImage: {
    }
    }
  },
  xAxis: {
    
    type: 'category',
    boundaryGap: false,
    data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  },
  yAxis: {
    
    type: 'value'
  },
  series: [
    {
    
      name: 'Email',
      type: 'line',
      stack: 'Total',
      data: [120, 132, 101, 134, 90, 230, 210]
    },
    {
    
      name: 'Email',
      type: 'line',
      stack: 'Total',
      data: [220, 182, 191, 234, 290, 330, 310]
    },
    {
    
      name: 'Video Ads',
      type: 'line',
      stack: 'Total',
      data: [150, 232, 201, 154, 190, 330, 410]
    },
    {
    
      name: 'Direct',
      type: 'line',
      stack: 'Total',
      data: [320, 332, 301, 334, 390, 330, 320]
    },
    {
    
      name: 'Search Engine',
      type: 'line',
      stack: 'Total',
      data: [820, 932, 901, 934, 1290, 1330, 1320]
    }
  ]
};

When the line chart has the same name , Also show all the illustrations .

Solution logic ：
series In the series name Set unique value ;legend adopt formatter, Using uniqueness id Get the corresponding name to show ; Floating window passing data Medium value Array settings name To display .

Mainly used legend Of formatter Method

The contents of the floating window also need to be modified

option = {
    
  title: {
    
    text: 'Stacked Line'
  },
  tooltip: {
    
    trigger: 'axis',
    formatter: (params) => {
    
      let arr = [
        {
    
          name: '3333',
          type: 'line',
          text: 'Videot',
          data: [120, 132, 101, 134, 90, 230, 210]
        },
        {
    
          name: 'Videot',
          type: 'line',
          text: 'Videot',
          data: [220, 182, 191, 234, 290, 330, 310]
        },
        {
    
          name: 'Videot1',
          type: 'line',
          text: 'Videot',
          data: [150, 232, 201, 154, 190, 330, 410]
        },
        {
    
          name: 'Search Engine',
          type: 'line',
          text: 'Search Engine',
          data: [320, 332, 301, 334, 390, 330, 320]
        },
        {
    
          name: 'Search Engine1',
          type: 'line',
          text: 'Search Engine',
          data: [820, 932, 901, 934, 1290, 1330, 1320]
        }
      ];
      let middle = ``;
      for (let i = 0; i < params.length; i++) {
    
        let name = arr.find((v) => v.name === params[i].seriesName).text;
        middle += `<div> <span> ${
      name}</span>: <span>${
      params[i].value}</span> </div>`;
      }
      let content = ` <div> ${
      middle} </div>`;
      return content;
    }
  },
  legend: {
    
    show: true,
    // data: ['Email', 'Union Ads', 'Video Ads', 'Direct', 'Search Engine'],
    formatter: (name) => {
    
      let arr = [
        {
    
          name: '3333',
          type: 'line',
          text: 'Videot',
          data: [120, 132, 101, 134, 90, 230, 210]
        },
        {
    
          name: 'Videot',
          type: 'line',
          text: 'Videot',
          data: [220, 182, 191, 234, 290, 330, 310]
        },
        {
    
          name: 'Videot1',
          type: 'line',
          text: 'Videot',
          data: [150, 232, 201, 154, 190, 330, 410]
        },
        {
    
          name: 'Search Engine',
          type: 'line',
          text: 'Search Engine',
          data: [320, 332, 301, 334, 390, 330, 320]
        },
        {
    
          name: 'Search Engine1',
          type: 'line',
          text: 'Search Engine',
          data: [820, 932, 901, 934, 1290, 1330, 1320]
        }
      ];
      let showText = arr.find((v) => v.name === name).text;
      return showText;
    }
  },
  grid: {
    
    left: '3%',
    right: '4%',
    bottom: '3%',
    containLabel: true
  },
  toolbox: {
    
    feature: {
    
      saveAsImage: {
    }
    }
  },
  xAxis: {
    
    type: 'category',
    boundaryGap: false,
    data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  },
  yAxis: {
    
    type: 'value'
  },
  series: [
    {
    
      name: '3333',
      type: 'line',
      data: [120, 132, 101, 134, 90, 230, 210]
    },
    {
    
      name: 'Videot',
      type: 'line',
      data: [220, 182, 191, 234, 290, 330, 310]
    },
    {
    
      name: 'Videot1',
      type: 'line',
      data: [150, 232, 201, 154, 190, 330, 410]
    },
    {
    
      name: 'Search Engine',
      type: 'line',
      data: [320, 332, 301, 334, 390, 330, 320]
    },
    {
    
      name: 'Search Engine1',
      type: 'line',
      data: [820, 932, 901, 934, 1290, 1330, 1320]
    }
  ]
};