define the controller and service for the airport management

src/airport/airport.service.ts

@@ -0,0 +1,64 @@
+import { Injectable } from '@nestjs/common';
+import { InjectModel } from '@nestjs/mongoose';
+import { Model } from 'mongoose';
+import { Airport, AirportDocument } from './models/airport.model';
+
+@Injectable()
+export class AirportService {
+  constructor(
+    @InjectModel('airport')
+    private readonly airportModel: Model<AirportDocument>,
+  ) {}
+
+  private async airportExists(icao: string): Promise<boolean> {
+    return this.airportModel
+      .find({ icao })
+      .then((response) => response && response.length !== 0);
+  }
+
+  async airportsList(): Promise<string[]> {
+    return this.airportModel.find({}).then((response) => {
+      const icaoCodes: string[] = [];
+      response.forEach((airport) => icaoCodes.push(airport.icao));
+      return icaoCodes;
+    });
+  }
+
+  async airport(icao: string): Promise<Airport> {
+    return this.airportModel.find({ icao }).then((response) => {
+      if (!response || response.length !== 1) return null;
+      return response[0];
+    });
+  }
+
+  async registerAirport(airport: Airport): Promise<boolean> {
+    this.airportExists(airport.icao).then(async (exists) => {
+      if (!exists) {
+        await this.airportModel.create(airport);
+      }
+
+      return !exists;
+    });
+
+    return false;
+  }
+
+  async updateAirport(airport: Airport): Promise<boolean> {
+    this.airportExists(airport.icao).then(async (exists) => {
+      if (exists) {
+        await this.airportModel.findOneAndUpdate(
+          { icao: airport.icao },
+          airport,
+        );
+      }
+
+      return exists;
+    });
+
+    return false;
+  }
+
+  async deleteAirport(icao: string): Promise<void> {
+    this.airportModel.deleteOne({ icao });
+  }
+}