How to use the aurelia-slickgrid.Editors.longText function in aurelia-slickgrid

minWidth: 30,
        maxWidth: 30,
        // use onCellClick OR grid.onClick.subscribe which you can see down below
        onCellClick: (e: Event, args: OnEventArgs) => {
          console.log(args);
          if (confirm('Are you sure?')) {
            this.aureliaGrid.gridService.deleteDataGridItemById(args.dataContext.id);
          }
        }
      },
      {
        id: 'title', name: 'Title', field: 'title',
        sortable: true,
        type: FieldType.string,
        editor: {
          model: Editors.longText
        }
      },
      {
        id: 'duration', name: 'Duration (days)', field: 'duration',
        sortable: true,
        type: FieldType.number,
        editor: {
          model: Editors.text
        },
        onCellChange: (e: Event, args: OnEventArgs) => {
          alert('onCellChange directly attached to the column definition');
          console.log(args);
        }
      },
      {
        id: 'complete', name: '% Complete', field: 'percentComplete',

// use onCellClick OR grid.onClick.subscribe which you can see down below
      /*
      onCellClick: (e: Event, args: OnEventArgs) => {
        console.log(args);
        this.alertWarning = `Deleting: ${args.dataContext.title}`;
      }
      */
    }, {
      id: 'title',
      name: 'Title',
      field: 'title',
      filterable: true,
      sortable: true,
      type: FieldType.string,
      editor: {
        model: Editors.longText,
        validator: myCustomTitleValidator // use a custom validator
      },
      minWidth: 100,
      onCellChange: (e, args) => {
        console.log(args);
        this.alertWarning = `Updated Title: ${args.dataContext.title}`;
      }
    }, {
      id: 'title2',
      name: 'Title, Custom Editor',
      field: 'title',
      filterable: true,
      sortable: true,
      type: FieldType.string,
      editor: {
        model: CustomInputEditor,

// use onCellClick OR grid.onClick.subscribe which you can see down below
        /*
        onCellClick: (e: Event, args: OnEventArgs) => {
          console.log(args);
          this.alertWarning = `Deleting: ${args.dataContext.title}`;
        }
        */
      }, {
        id: 'title',
        name: 'Title',
        field: 'title',
        filterable: true,
        sortable: true,
        type: FieldType.string,
        editor: {
          model: Editors.longText,
          validator: myCustomTitleValidator, // use a custom validator
        },
        minWidth: 100,
        onCellChange: (e: Event, args: OnEventArgs) => {
          console.log(args);
          this.alertWarning = `Updated Title: ${args.dataContext.title}`;
        }
      }, {
        id: 'title2',
        name: 'Title, Custom Editor',
        field: 'title',
        filterable: true,
        sortable: true,
        type: FieldType.string,
        editor: {
          model: CustomInputEditor,

this.gridExtraService.highlightRow(args.row, 1500);
          this.gridExtraService.setSelectedRow(args.row);
        }
      },
      {
        id: 'delete', field: 'id',
        formatter: Formatters.deleteIcon,
        minWidth: 30,
        maxWidth: 30,
        // use onCellClick OR grid.onClick.subscribe which you can see down below
        onCellClick: (args: OnEventArgs) => {
          console.log(args);
          alert(`Deleting: ${args.dataContext.title}`);
        }
      },
      { id: 'title', name: 'Title', field: 'title', sortable: true, type: FieldType.string, editor: Editors.longText, minWidth: 100 },
      { id: 'duration', name: 'Duration (days)', field: 'duration', sortable: true, type: FieldType.number, editor: Editors.text, minWidth: 100 },
      { id: 'complete', name: '% Complete', field: 'percentComplete', formatter: Formatters.percentCompleteBar, type: FieldType.number, editor: Editors.integer, minWidth: 100 },
      { id: 'start', name: 'Start', field: 'start', formatter: Formatters.dateIso, sortable: true, minWidth: 100, type: FieldType.date, editor: Editors.date },
      { id: 'finish', name: 'Finish', field: 'finish', formatter: Formatters.dateIso, sortable: true, minWidth: 100, type: FieldType.date, editor: Editors.date },
      { id: 'effort-driven', name: 'Effort Driven', field: 'effortDriven', formatter: Formatters.checkmark, type: FieldType.number, editor: Editors.checkbox, minWidth: 100 }
    ];

    this.gridOptions = {
      asyncEditorLoading: false,
      autoEdit: this.isAutoEdit,
      autoResize: {
        containerId: 'demo-container',
        sidePadding: 15
      },
      editable: true,
      enableCellNavigation: true

defineGrid() {
    this.columnDefinitions = [
      {
        id: 'title', name: 'Title', field: 'title',
        sortable: true,
        type: FieldType.string,
        editor: {
          model: Editors.longText
        }
      },
      {
        id: 'duration', name: 'Duration (days)', field: 'duration',
        sortable: true,
        type: FieldType.number,
        editor: {
          model: Editors.text
        },
        onCellChange: (e, args) => {
          alert('onCellChange directly attached to the column definition');
          console.log(args);
        }
      },
      {
        id: 'complete', name: '% Complete', field: 'percentComplete',

defineGrid() {
    this.columnDefinitions = [
      { id: 'title', name: 'Title', field: 'title', sortable: true, type: FieldType.string, editor: Editors.longText },
      {
        id: 'duration', name: 'Duration (days)', field: 'duration', sortable: true, type: FieldType.number, editor: Editors.text,
        onCellChange: (args: OnEventArgs) => {
          alert('onCellChange directly attached to the column definition');
          console.log(args);
        }
      },
      { id: 'complete', name: '% Complete', field: 'percentComplete', formatter: Formatters.percentCompleteBar, type: FieldType.number, editor: Editors.integer },
      { id: 'start', name: 'Start', field: 'start', formatter: Formatters.dateIso, sortable: true, type: FieldType.date/*, editor: Editors.date*/ },
      { id: 'finish', name: 'Finish', field: 'finish', formatter: Formatters.dateIso, sortable: true, type: FieldType.date },
      { id: 'effort-driven', name: 'Effort Driven', field: 'effortDriven', formatter: Formatters.checkmark, type: FieldType.number, editor: Editors.checkbox }
    ];

    this.gridOptions = {
      asyncEditorLoading: false,
      autoResize: {