<lightning-datatable
                    columns={columns}
                    data={data}
                    key-field="id"
                    enable-infinite-loading
                    onloadmore={loadMoreData}>
            </lightning-datatable>
---------------------------------------------------------------------------------

js

  data = [];
    columns = columnsDefs;
    loadMoreStatus;
    @api totalNumberOfRows;

    loadMoreData(event) {
         
            event.target.isLoading = true;
          
            this.loadMoreStatus = 'Loading';
            fetchData(50)
                .then((data) => {
                    if (data.length >= this.totalNumberOfRows) {
                        event.target.enableInfiniteLoading = false;
                        this.loadMoreStatus = 'No more data to load';
                    } else {
                        const currentData = this.data;
                        
                        const newData = currentData.concat(data);
                        this.data = newData;
                        this.loadMoreStatus = '';
                    }
                    event.target.isLoading = false;
                });
        }