Add type definitions for get() (#4096)

* Add type definitions for get()

* cleanup

* Update .changeset/many-snails-kneel.md

Co-authored-by: Feiyang <[email protected]>

* more specific changelog

Co-authored-by: Feiyang <[email protected]>

Author: jmwski

.changeset/many-snails-kneel.md

@@ -0,0 +1,5 @@
+---
+"firebase": patch
+---
+
+Add the missing type definition for 'Query.get()' for RTDB

packages/database-types/index.d.ts

@@ -81,6 +81,7 @@ export interface Query {
     callback?: (a: DataSnapshot, b?: string | null) => any,
     context?: Object | null
   ): void;
+  get(): Promise<DataSnapshot>;
   on(
     eventType: EventType,
     callback: (a: DataSnapshot, b?: string | null) => any,

packages/firebase/index.d.ts

@@ -6171,6 +6171,16 @@ declare namespace firebase.database {
       context?: Object | null
     ): void;
 
+    /**
+     * Gets the most up-to-date result for this query.
+     *
+     * @return A promise which resolves to the resulting DataSnapshot if
+     * a value is available, or rejects if the client is unable to return
+     * a value (e.g., if the server is unreachable and there is nothing
+     * cached).
+     */
+    get(): Promise<DataSnapshot>;
+
     /**
      * Listens for data changes at a particular location.
      *