How to add default headerTooltip in ag-grid which is the same value as the data in the cell?

As the title says, I am using ag-grid and I want to add default tooltip on every grid in my app. The value of the tooltip should be the same as the value of the cell someone is hovering. I have tried using:

this.gridOptions.defaultColDef = {
 tooltip: (params) => {
  return params.value;
 }
};

but this doesn't do anything.

I do not want to add it in columnDefs, because then I would have to do it for every single column. Can anyone help?

Thank you.

You need to use the tooltipValueGetter property and set this in defaultColDef to params.value.

defaultColDef = {
      tooltipValueGetter: (params) => {
        return params.value;
      }
    };

Demo.