feat(GeoTransaction): add delete function

src/GeoFirestore.ts

@@ -45,7 +45,7 @@ export class GeoFirestore {
    * corresponding failure error will be returned.
    */
   public runTransaction(
-    updateFunction: (transaction: GeoTransaction | GeoFirestoreTypes.cloud.Transaction | GeoFirestoreTypes.web.Transaction) => Promise<any>
+    updateFunction: (transaction: GeoFirestoreTypes.cloud.Transaction | GeoFirestoreTypes.web.Transaction) => Promise<any>
   ): Promise<any> {
     return (this._firestore as GeoFirestoreTypes.web.Firestore).runTransaction(updateFunction);
   }

src/GeoTransaction.ts

@@ -1,4 +1,5 @@
 import { GeoFirestoreTypes } from './GeoFirestoreTypes';
+import { GeoDocumentReference } from './GeoDocumentReference';
 
 /**
  * A reference to a transaction. The `GeoTransaction` object passed to a transaction's updateFunction provides the methods to read and
@@ -10,4 +11,19 @@ export class GeoTransaction {
       throw new Error('Transaction must be an instance of a Firestore Transaction');
     }
   }
+
+  /**
+   * Deletes the document referred to by the provided `GeoDocumentReference` or `DocumentReference`.
+   *
+   * @param documentRef A reference to the document to be deleted.
+   * @return This `GeoTransaction` instance. Used for chaining method calls.
+   */
+  public delete(
+    documentRef: GeoDocumentReference | GeoFirestoreTypes.cloud.DocumentReference | GeoFirestoreTypes.web.DocumentReference
+  ): GeoTransaction {
+    const ref = ((documentRef instanceof GeoDocumentReference) ?
+      documentRef['_document'] : documentRef) as GeoFirestoreTypes.web.DocumentReference;
+    (this._transaction as GeoFirestoreTypes.web.Transaction).delete(ref);
+    return this;
+  }
 }