How to handle complex rowspan in angular 6?

I have created table from the below mentioned JSON which works fine. I have certain condition that needs to be handled. the function which i used is also mentioned here.I also attached output image for the same.Help for the same is highly appreciated… Thanks in advance Conditions :

• if email row is empty need to remove that particular row.
• Let’s say value2 has one value in email, in that case it should be displayed.

    

        rows = [];
    
    generateTable() {
      if (!this.data) {
        return;
      }
    
      this.rows.push([
        {
          text: this.data.e_o_name,
          rowspan: 0
        }
      ]);
      let maxRowSpan = 0;
    
      this.data.matching_details.forEach((detail, i) => {
        const elemRowSpan = Math.max(detail.matching_attributes.length, 1);
        maxRowSpan += elemRowSpan;
    
        if (i > 0) {
          this.rows.push([])
        }
        this.rows[this.rows.length - 1].push({
          text: detail.me_value,
          rowspan: elemRowSpan
        });
    
        detail.matching_attributes.forEach((attr, j) => {
          if (j > 0) {
            this.rows.push([])
          }
    
          const mail = attr.me_list[0];
          this.rows[this.rows.length - 1].push(
            {
              text: attr.me_name,
              rowspan: 1
            },
            {
              text: mail.me_email_list.map(({ me_value }) => me_value).join(', '),
              rowspan: 1
            },
            {
              text: mail.me_percent,
              rowspan: 1
            }
          );
        })
      });
      this.rows[0][0].rowspan = maxRowSpan;
    }
    
    ```
    #Josn : #
    ```
    
{
   "e_id":"1234",
   "e_o_name":"Contact_info",
   "matching_details":[
      {
         "me_value":"value1",
         "matching_attributes":[
            {
               "me_id":"1234",
               "me_name":"28 sai",
               "me_list":[
                  {
                     "me_type":"Email ID",
                     "me_email_list":[
                        {
                           "me_value":"a@gmail"
                        },
                        {
                           "me_value":"b@gmail"
                        }
                     ],
                     "me_percent":"100"
                  }
               ]
            },
            {
               "me_id":"5678",
               "me_name":"29 meena",
               "me_list":[
                  {
                     "me_type":"Email ID",
                     "me_email_list":[
                        {
                           "me_value":"[e-mail]"
                        },
                        {
                           "me_value":",[e-mail]"
                        }
                     ],
                     "me_percent":"100"
                  }
               ]
            }
         ]
      },
      {
         "me_value":"value2",
         "matching_attributes":[
            {
               "me_id":"1234",
               "me_name":"rimzim",
               "me_list":[
                  {
                     "me_type":"Email ID",
                     "me_email_list":[
                        {
                           "me_value":"p@gmail"
                        },
                        {
                           "me_value":"q@gmail"
                        }
                     ],
                     "me_percent":"100"
                  }
               ]
            },
            {
               "me_id":"5678",
               "me_name":"ranu",
               "me_list":[
                  {
                     "me_type":"Email ID",
                     "me_email_list":[
                        {
                           "me_value":"[e-mail]"
                        },
                        {
                           "me_value":",[e-mail]"
                        }
                     ],
                     "me_percent":"100"
                  }
               ]
            }
         ]
      }
   ]
}

Answer

Seems like you want to put in column (attr) level validations, so in the html while looping through it you will need to implement the checks

https://stackblitz.com/edit/angular-zm1ap1?file=src/app/app.component.html

<table>
    <tbody>
        <tr>
            <th>contact</th>
            <th>ty</th>
            <th>ed</th>
            <th>mail</th>
            <th>percent</th>
        </tr>
        <tr *ngFor="let row of rows">
      <!-- check if row is empty or could add additional check such 
      row[3].text (email) is true 
       -->
      <ng-container *ngIf='row && row.length > 0'> 
      <td [attr.rowspan]='row[0].rowspan'>{{row[0].text}}</td>
      <td *ngIf='row.length > 1' [attr.rowspan]='row[1].rowspan'>{{row[1].text}}</td>
      
      <td *ngIf='row.length > 2' [attr.rowspan]='row[2].rowspan'>{{row[2].text}}</td>
      <td *ngIf='row.length > 3' [attr.rowspan]='row[3].rowspan'>{{row[3].text}}</td>
      <td *ngIf='row.length > 4' [attr.rowspan]='row[4].rowspan'>{{row[4].text}}</td>
      </ng-container>
        </tr>

    </tbody>
</table>