From 4e415b51b14be86924c9bcc5d7e6a4a0021a2cc3 Mon Sep 17 00:00:00 2001
From: Robin Genz <mail@robingenz.dev>
Date: Mon, 25 May 2026 10:32:05 +0200
Subject: [PATCH 1/2] fix(firestore): generate unique listener IDs

Listener IDs were derived from `Date.now()`, so listeners created in the
same millisecond shared an ID and overwrote each other in the
unsubscribes map, leaving the earlier ones unable to be removed.

Replace the timestamp with a per-instance incrementing counter. The same
issue was present in the storage plugin (downloadFile/uploadFile
callback IDs) and is fixed here as well.

Closes #986
---
 packages/firestore/src/web.ts | 11 ++++++++---
 packages/storage/src/web.ts   | 10 ++++++++--
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/packages/firestore/src/web.ts b/packages/firestore/src/web.ts
index 3319d6857..a5279c495 100644
--- a/packages/firestore/src/web.ts
+++ b/packages/firestore/src/web.ts
@@ -96,6 +96,7 @@ export class FirebaseFirestoreWeb
   implements FirebaseFirestorePlugin
 {
   private readonly unsubscribesMap: Map<string, Unsubscribe> = new Map();
+  private lastListenerId = 0;
 
   public async addCollectionGroupSnapshotListener<
     T extends DocumentData = DocumentData,
@@ -129,7 +130,7 @@ export class FirebaseFirestoreWeb
       },
       error => callback(null, error),
     );
-    const id = Date.now().toString();
+    const id = this.generateListenerId();
     this.unsubscribesMap.set(id, unsubscribe);
     return id;
   }
@@ -166,7 +167,7 @@ export class FirebaseFirestoreWeb
       },
       error => callback(null, error),
     );
-    const id = Date.now().toString();
+    const id = this.generateListenerId();
     this.unsubscribesMap.set(id, unsubscribe);
     return id;
   }
@@ -220,7 +221,7 @@ export class FirebaseFirestoreWeb
       },
       error => callback(null, error),
     );
-    const id = Date.now().toString();
+    const id = this.generateListenerId();
     this.unsubscribesMap.set(id, unsubscribe);
     return id;
   }
@@ -670,4 +671,8 @@ export class FirebaseFirestoreWeb
         return marker;
     }
   }
+
+  private generateListenerId(): string {
+    return (++this.lastListenerId).toString();
+  }
 }
diff --git a/packages/storage/src/web.ts b/packages/storage/src/web.ts
index 2237dfc2b..d69a2e98c 100644
--- a/packages/storage/src/web.ts
+++ b/packages/storage/src/web.ts
@@ -43,6 +43,8 @@ export class FirebaseStorageWeb
 {
   public static readonly ERROR_BLOB_MISSING = 'blob must be provided.';
 
+  private lastCallbackId = 0;
+
   public async downloadFile(
     options: DownloadFileOptions,
     callback: DownloadFileCallback,
@@ -63,7 +65,7 @@ export class FirebaseStorageWeb
       .catch(error => {
         callback(null, error);
       });
-    return Date.now().toString();
+    return this.generateCallbackId();
   }
 
   public async deleteFile(options: DeleteFileOptions): Promise<void> {
@@ -179,7 +181,7 @@ export class FirebaseStorageWeb
         callback(result, undefined);
       },
     });
-    return Date.now().toString();
+    return this.generateCallbackId();
   }
 
   public async useEmulator(options: UseEmulatorOptions): Promise<void> {
@@ -199,4 +201,8 @@ export class FirebaseStorageWeb
     };
     return result;
   }
+
+  private generateCallbackId(): string {
+    return (++this.lastCallbackId).toString();
+  }
 }

From 385702178f93d542c7ded39dad993339009c373f Mon Sep 17 00:00:00 2001
From: Robin Genz <mail@robingenz.dev>
Date: Mon, 25 May 2026 10:35:11 +0200
Subject: [PATCH 2/2] chore: add changeset

---
 .changeset/firestore-storage-unique-listener-ids.md | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 .changeset/firestore-storage-unique-listener-ids.md

diff --git a/.changeset/firestore-storage-unique-listener-ids.md b/.changeset/firestore-storage-unique-listener-ids.md
new file mode 100644
index 000000000..01d6e5387
--- /dev/null
+++ b/.changeset/firestore-storage-unique-listener-ids.md
@@ -0,0 +1,6 @@
+---
+'@capacitor-firebase/firestore': patch
+'@capacitor-firebase/storage': patch
+---
+
+fix: generate unique listener/callback IDs on web so listeners created in the same millisecond do not overwrite each other