Add check before dropping collection

src/services/dbAccess.services.js

@@ -13,20 +13,24 @@ const client = new MongoClient(uri);
 const db = client.db(dbName);
 
 async function dropCollection(coll){
-    log.out(`DbAccess.dropCollection: checking if collection exists: ${coll}`)
-
-    //Some Code Here:
     await client.connect();
-    var cols = await db.listCollections().toArray()
+
-    log.out(`dbAccess.dropCollection: Existing collections: ${JSON.stringify(cols)}`)
+    // check if collection contains any documents, if it doesn't, it is either empty or non-existent - it doesn't need dropping.
+    var collection = db.collection(coll);
+    var count = await collection.countDocuments();
+    log.out(`DbAccess.dropCollection: Collection '${coll}' contains ${count} documents`)
+    if (count == 0) {
+        log.out(`DbAccess.dropCollection: Collection '${coll}' is empty.  Do not need to drop`)
+    } else {
+        log.out(`DbAccess.dropCollection: dropping collection: '${coll}'`)
+        db.dropCollection(coll);
+        log.out(`DbAccess.dropCollection: dropped collection: '${coll}'`)
+    }
+    // ALTERNATIVE METHOD - Appears to not be needed:
+    // This code returns and prints an array containing an object for each existing collection.
+//    var cols = await db.listCollections().toArray()
+//    log.out(`dbAccess.dropCollection: Existing collections: ${JSON.stringify(cols)}`)
     // If (any object in the Array contains name:{coll} then exsists.  If not doesn't exist.)
-
-
-    // If Collection Exists:
-    log.out(`DbAccess.dropCollection: dropping collection: ${coll}`)
-    db.dropCollection(coll);
-    log.out(`DbAccess.dropCollection: dropped collection: ${coll}`)
-    // Else Do Nothing
 }
 
 async function putCorpus(data){