How to use the @lumino/datagrid.JSONModel function in @lumino/datagrid

function createModel(): JSONModel {
      return new JSONModel({
        data: [
          { index: 0, a: 'other', b: 'match 1' },
          { index: 1, a: 'other', b: 'match 2' }
        ],
        schema: {
          primaryKey: ['index'],
          fields: [
            {
              name: 'a'
            },
            { name: 'b' }
          ]
        }
      });
    }
    function createGridSearchService(model: JSONModel): GridSearchService {

function main(): void {

  let model1 = new LargeDataModel();
  let model2 = new StreamingDataModel();
  let model3 = new RandomDataModel(15, 10);
  let model4 = new RandomDataModel(80, 80);
  let model5 = new JSONModel(Data.cars);

  let blueStripeStyle: DataGrid.Style = {
    ...DataGrid.defaultStyle,
    rowBackgroundColor: i => i % 2 === 0 ? 'rgba(138, 172, 200, 0.3)' : '',
    columnBackgroundColor: i => i % 2 === 0 ? 'rgba(100, 100, 100, 0.1)' : ''
  };

  let brownStripeStyle: DataGrid.Style = {
    ...DataGrid.defaultStyle,
    columnBackgroundColor: i => i % 2 === 0 ? 'rgba(165, 143, 53, 0.2)' : ''
  };

  let greenStripeStyle: DataGrid.Style = {
    ...DataGrid.defaultStyle,
    rowBackgroundColor: i => i % 2 === 0 ? 'rgba(64, 115, 53, 0.2)' : ''
  };