feat(GeoTransaction): stub GeoTransaction class

src/GeoFirestore.ts

@@ -1,5 +1,6 @@
 import { GeoFirestoreTypes } from './GeoFirestoreTypes';
 import { GeoCollectionReference } from './GeoCollectionReference';
+import { GeoTransaction } from './GeoTransaction';
 import { GeoWriteBatch } from './GeoWriteBatch';
 
 /**
@@ -33,4 +34,19 @@ export class GeoFirestore {
   public collection(collectionPath: string): GeoCollectionReference {
     return new GeoCollectionReference(this._firestore.collection(collectionPath));
   }
+
+  /**
+   * Executes the given updateFunction and then attempts to commit the changes applied within the transaction. If any document read within
+   * the transaction has changed, the updateFunction will be retried. If it fails to commit after 5 attempts, the transaction will fail.
+   *
+   * @param updateFunction The function to execute within the transaction context.
+   * @return If the transaction completed successfully or was explicitly aborted (by the updateFunction returning a failed Promise), the
+   * Promise returned by the updateFunction will be returned here. Else if the transaction failed, a rejected Promise with the
+   * corresponding failure error will be returned.
+   */
+  public runTransaction(
+    updateFunction: (transaction: GeoTransaction | GeoFirestoreTypes.cloud.Transaction | GeoFirestoreTypes.web.Transaction) => Promise<any>
+  ): Promise<any> {
+    return (this._firestore as GeoFirestoreTypes.web.Firestore).runTransaction(updateFunction);
+  }
 }

src/GeoFirestoreTypes.ts

@@ -47,6 +47,7 @@ export namespace GeoFirestoreTypes {
     export type Query = FirestoreTypes.Query;
     export type QuerySnapshot = FirestoreTypes.QuerySnapshot;
     export type QueryDocumentSnapshot = FirestoreTypes.QueryDocumentSnapshot;
+    export type Transaction = FirestoreTypes.Transaction;
     export type WriteBatch = FirestoreTypes.WriteBatch;
   }
   export namespace cloud {
@@ -60,6 +61,7 @@ export namespace GeoFirestoreTypes {
     export type Query = FirebaseFirestore.Query;
     export type QuerySnapshot = FirebaseFirestore.QuerySnapshot;
     export type QueryDocumentSnapshot = FirebaseFirestore.QueryDocumentSnapshot;
+    export type Transaction = FirebaseFirestore.Transaction;
     export type WriteBatch = FirebaseFirestore.WriteBatch;
   }
 }

src/GeoTransaction.ts

@@ -0,0 +1,13 @@
+import { GeoFirestoreTypes } from './GeoFirestoreTypes';
+
+/**
+ * A reference to a transaction. The `GeoTransaction` object passed to a transaction's updateFunction provides the methods to read and
+ * write data within the transaction context. See `GeoFirestore.runTransaction()`.
+ */
+export class GeoTransaction {
+  constructor(private _transaction: GeoFirestoreTypes.cloud.Transaction | GeoFirestoreTypes.web.Transaction) {
+    if (Object.prototype.toString.call(_transaction) !== '[object Object]') {
+      throw new Error('Transaction must be an instance of a Firestore Transaction');
+    }
+  }
+}