Fixes access on deeply nested, nonexistent property

CHANGELOG.md

@@ -1,2 +1,3 @@
+- Fixes access on deeply nested, nonexistent property. (#1432)
 - Add features to task queue functions. (#1423)
 - Add traces to V2 Firestore trigger logs. (#1440)

spec/v1/providers/database.spec.ts

@@ -458,6 +458,7 @@ describe("DataSnapshot", () => {
       populate(applyChange({ a: 23 }, { b: 33 }));
       expect(subject.child("a/b").val()).to.be.null;
       expect(subject.child("b/c").val()).to.be.null;
+      expect(subject.child("a/b/c").val()).to.be.null;
     });
 
     it("should return a leaf value", () => {

src/common/providers/database.ts

@@ -120,6 +120,9 @@ export class DataSnapshot implements database.DataSnapshot {
     let source = this._data;
     if (parts.length) {
       for (const part of parts) {
+        if (source[part] === undefined) {
+          return null;
+        }
         source = source[part];
       }
     }

src/v2/options.ts

@@ -260,7 +260,7 @@ export function getGlobalOptions(): GlobalOptions {
  * Additional fields that can be set on any event-handling function.
  */
 export interface EventHandlerOptions extends Omit<GlobalOptions, "enforceAppCheck"> {
-   /** Type of the event. Valid values are TODO */
+  /** Type of the event. Valid values are TODO */
   eventType?: string;
 
   /** TODO */