fix Typescript delete must be on optional error (#89)

* fix Typescript delete must be on optional error

* don't query dummy stop_lat and stop_lon

* combine Object.assign with spread operation

* Revert "combine Object.assign with spread operation"

This reverts commit ec5c765.

---------

Co-authored-by: Michael Tsang <michael.tsang@jnction.co.uk>

src/gtfs/repository/CIFRepository.ts

@@ -46,14 +46,12 @@ export class CIFRepository {
    * Return all the stops with some configurable long/lat applied
    */
   public async getStops(): Promise<Stop[]> {
-    const [results] = await this.db.query<(Stop & {easting : number, northing : number})>(`
+    const [results] = await this.db.query<Omit<Stop, 'stop_lat' | 'stop_lon'> & {easting : number, northing : number}>(`
       SELECT
         crs_code AS stop_id, 
         tiploc_code AS stop_code,
         station_name AS stop_name,
         cate_interchange_status AS stop_desc,
-        0 AS stop_lat,
-        0 AS stop_lon,
         NULL AS zone_id,
         NULL AS stop_url,
         NULL AS location_type,
@@ -67,12 +65,9 @@ export class CIFRepository {
     `);
 
     // overlay the long and latitude values from configuration
-    return results.map(stop => {
-      const [stop_lon, stop_lat] = proj4('EPSG:27700', 'EPSG:4326', [(stop.easting - 10000) * 100, (stop.northing - 60000) * 100]);
-      stop.stop_lon = stop_lon;
-      stop.stop_lat = stop_lat;
-      delete stop.easting;
-      delete stop.northing;
+    return results.map(row => {
+      const [stop_lon, stop_lat] = proj4('EPSG:27700', 'EPSG:4326', [(row.easting - 10000) * 100, (row.northing - 60000) * 100]);
+      const {easting, northing, ...stop} = {...row, stop_lon, stop_lat};
       return Object.assign(stop, this.stationCoordinates[stop.stop_id]);
     });
   }