generate json array object or json object from angular material table

Question

Actually the requirement is to generate json array object or json object from angular material table so that I can use this object and export to Excel sheet.

Below is the data.

const ELEMENT_DATA: Element[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
  {position: 11, name: 'Sodium', weight: 22.9897, symbol: 'Na'},
  {position: 12, name: 'Magnesium', weight: 24.305, symbol: 'Mg'},
  {position: 13, name: 'Aluminum', weight: 26.9815, symbol: 'Al'},
  {position: 14, name: 'Silicon', weight: 28.0855, symbol: 'Si'},
  {position: 15, name: 'Phosphorus', weight: 30.9738, symbol: 'P'},
  {position: 16, name: 'Sulfur', weight: 32.065, symbol: 'S'},
  {position: 17, name: 'Chlorine', weight: 35.453, symbol: 'Cl'},
  {position: 18, name: 'Argon', weight: 39.948, symbol: 'Ar'},
  {position: 19, name: 'Potassium', weight: 39.0983, symbol: 'K'},
  {position: 20, name: 'Calcium', weight: 40.078, symbol: 'Ca'},
];

Below is the Material table.

<div class="example-container mat-elevation-z8">
  <mat-table #table [dataSource]="dataSource">

    <!--- Note that these columns can be defined in any order.
          The actual rendered columns are set as a property on the row definition" -->

    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>
    </ng-container>

    <!-- Name Column -->
    <ng-container matColumnDef="name">
      <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.name}} </mat-cell>
    </ng-container>

    <!-- Weight Column -->
    <ng-container matColumnDef="weight">
      <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.weight}} </mat-cell>
    </ng-container>

    <!-- Symbol Column -->
    <ng-container matColumnDef="symbol">
      <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.symbol}} </mat-cell>
    </ng-container>

    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
    <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
  </mat-table>
</div>

I want to generate json object of this material table.

Answer 1

If your ultimate aim is to download excel sheet, then you can do so directly from the ELEMENT_DATA instead of doing it from material table.

ts file

const Element=[  
{position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
{position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
{position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
{position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
{position: 5, name: 'Boron', weight: 10.811, symbol: 'B'}
];
DownloadAsExcel()
{
const worksheet: XLSX.WorkSheet=XLSX.utils.table_to_sheet(this.table.nativeElement);
const tbltojson = (JSON.parse(JSON.stringify(worksheet)));
const workbook: XLSX.WorkbBook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(workbook, worksheet, 'Sheet1');  //can use 'tbltojson' instead of 'worksheet'to download excel from a JSON object. Both work similarly
/* save to file */
XLSX.writeFile(workbook, 'YourFileName.xlsx');
}

Your downloaded excel looks like this: also import the xlsx module, so that the code doesn't show any error.

or if you need a json object then try converting the ELEMENT_DATA into a json like:

JSON.parse(JSON.stringify(Element));

the JSON will be like: