added auto increment to tracks

backend/package.json

@@ -23,6 +23,7 @@
     "joi": "^17.9.1",
     "jsonwebtoken": "^9.0.0",
     "mongoose": "^7.0.1",
+    "mongoose-sequence": "^5.3.1",
     "multer": "^1.4.5-lts.1",
     "ts-node-dev": "^2.0.0"
   },
@@ -31,6 +32,7 @@
     "@types/express": "^4.17.17",
     "@types/jsonwebtoken": "^9.0.1",
     "@types/mongoose": "^5.11.97",
+    "@types/mongoose-sequence": "^3.0.7",
     "@types/multer": "^1.4.7"
   }
 }

backend/src/interfaces/ITrack.ts

@@ -4,4 +4,5 @@ export default interface ITrack {
 	name: string;
 	album: ObjectId;
 	duration: string;
+	seq?: Number;
 }

backend/src/models/track.ts

-import {model, Schema} from 'mongoose';
+import mongoose, {model, Schema} from 'mongoose';
 import ITrack from '../interfaces/ITrack';
 
 const TrackSchema = new Schema<ITrack>(
@@ -19,9 +19,18 @@ const TrackSchema = new Schema<ITrack>(
 			required: [true, 'Duration is required'],
 			trim: true,
 		},
+		seq: {
+			type: Number,
+		},
 	},
 	{versionKey: false}
 );
 
+TrackSchema.pre('save', {document: true, query: false}, async function () {
+	const count = await TrackModel.count();
+	this.seq = count + 1;
+});
+
 const TrackModel = model<ITrack>('track', TrackSchema);
+
 export default TrackModel;