// Memory cache is the default if no config is specified.initializeFirestore(app);// This is the default behavior if no persistence is specified.initializeFirestore(app,{localCache:memoryLocalCache()});// Defaults to single-tab persistence if no tab manager is specified.initializeFirestore(app,{localCache:persistentLocalCache(/*settings*/{})});// Same as `initializeFirestore(app, {localCache: persistentLocalCache(/*settings*/{})})`,// but more explicit about tab management.initializeFirestore(app,{localCache:persistentLocalCache(/*settings*/{tabManager:persistentSingleTabManager()})});// Use multi-tab IndexedDb persistence.initializeFirestore(app,{localCache:persistentLocalCache(/*settings*/{tabManager:persistentMultipleTabManager()})});

firebase.firestore().enablePersistence().catch((err)=>{if(err.code=='failed-precondition'){// Multiple tabs open, persistence can only be enabled// in one tab at a a time.// ...}elseif(err.code=='unimplemented'){// The current browser does not support all of the// features required to enable persistence// ...}});// Subsequent queries will use persistence, if it was enabled successfully
test.firestore.js

letsettings=FirestoreSettings()// Use memory-only cachesettings.cacheSettings=MemoryCacheSettings(garbageCollectorSettings:MemoryLRUGCSettings())// Use persistent disk cache, with 100 MB cache sizesettings.cacheSettings=PersistentCacheSettings(sizeBytes:100*1024*1024asNSNumber)// Any additional options// ...// Enable offline data persistenceletdb=Firestore.firestore()db.settings=settings
ViewController.swift

FIRFirestoreSettings*settings=[[FIRFirestoreSettingsalloc]init];// Use memory-only cachesettings.cacheSettings=[[FIRMemoryCacheSettingsalloc]initWithGarbageCollectorSettings:[[FIRMemoryLRUGCSettingsalloc]init]];// Use persistent disk cache (default behavior)// This example uses 100 MB.settings.cacheSettings=[[FIRPersistentCacheSettingsalloc]initWithSizeBytes:@(100*1024*1024)];// Any additional options// ...// Enable offline data persistenceFIRFirestore*db=[FIRFirestorefirestore];db.settings=settings;
ViewController.m

valsettings=firestoreSettings{// Use memory cachesetLocalCacheSettings(memoryCacheSettings{})// Use persistent disk cache (default)setLocalCacheSettings(persistentCacheSettings{})}db.firestoreSettings=settings
DocSnippets.kt

FirebaseFirestoreSettingssettings=newFirebaseFirestoreSettings.Builder(db.getFirestoreSettings())// Use memory-only cache.setLocalCacheSettings(MemoryCacheSettings.newBuilder().build())// Use persistent disk cache (default).setLocalCacheSettings(PersistentCacheSettings.newBuilder().build()).build();db.setFirestoreSettings(settings);
DocSnippets.java

// Apple and Androiddb.settings=constSettings(persistenceEnabled:true);// Webawaitdb.enablePersistence(constPersistenceSettings(synchronizeTabs:true));
firestore.dart

import{initializeFirestore,CACHE_SIZE_UNLIMITED}from"firebase/firestore";constfirestoreDb=initializeFirestore(app,{cacheSizeBytes:CACHE_SIZE_UNLIMITED});
fs_setup_cache.js

firebase.firestore().settings({cacheSizeBytes:firebase.firestore.CACHE_SIZE_UNLIMITED});
test.firestore.js

// The default cache size threshold is 100 MB. Configure "cacheSizeBytes"// for a different threshold (minimum 1 MB) or set to "FirestoreCacheSizeUnlimited"// to disable clean-up.letsettings=Firestore.firestore().settings// Set cache size to 100 MBsettings.cacheSettings=PersistentCacheSettings(sizeBytes:100*1024*1024asNSNumber)Firestore.firestore().settings=settings
ViewController.swift

// The default cache size threshold is 100 MB. Configure "cacheSizeBytes"// for a different threshold (minimum 1 MB) or set to "kFIRFirestoreCacheSizeUnlimited"// to disable clean-up.FIRFirestoreSettings*settings=[FIRFirestorefirestore].settings;// Set cache size to 100 MBsettings.cacheSettings=[[FIRPersistentCacheSettingsalloc]initWithSizeBytes:@(100*1024*1024)];[FIRFirestorefirestore].settings=settings;
ViewController.m

// The default cache size threshold is 100 MB. Configure "setCacheSizeBytes"// for a different threshold (minimum 1 MB) or set to "CACHE_SIZE_UNLIMITED"// to disable clean-up.valsettings=FirebaseFirestoreSettings.Builder().setCacheSizeBytes(FirebaseFirestoreSettings.CACHE_SIZE_UNLIMITED).build()db.firestoreSettings=settings

// The default cache size threshold is 100 MB. Configure "setCacheSizeBytes"// for a different threshold (minimum 1 MB) or set to "CACHE_SIZE_UNLIMITED"// to disable clean-up.FirebaseFirestoreSettingssettings=newFirebaseFirestoreSettings.Builder().setCacheSizeBytes(FirebaseFirestoreSettings.CACHE_SIZE_UNLIMITED).build();db.setFirestoreSettings(settings);

db.settings=constSettings(persistenceEnabled:true,cacheSizeBytes:Settings.CACHE_SIZE_UNLIMITED,);
firestore.dart

import{collection,onSnapshot,where,query}from"firebase/firestore";constq=query(collection(db,"cities"),where("state","==","CA"));onSnapshot(q,{includeMetadataChanges:true},(snapshot)=>{snapshot.docChanges().forEach((change)=>{if(change.type==="added"){console.log("New city: ",change.doc.data());}constsource=snapshot.metadata.fromCache?"local cache":"server";console.log("Data came from "+source);});});
use_from_cache.js

db.collection("cities").where("state","==","CA").onSnapshot({includeMetadataChanges:true},(snapshot)=>{snapshot.docChanges().forEach((change)=>{if(change.type==="added"){console.log("New city: ",change.doc.data());}varsource=snapshot.metadata.fromCache?"local cache":"server";console.log("Data came from "+source);});});
test.firestore.js

// Listen to metadata updates to receive a server snapshot even if// the data is the same as the cached data.db.collection("cities").whereField("state",isEqualTo:"CA").addSnapshotListener(includeMetadataChanges:true){querySnapshot,erroringuardletsnapshot=querySnapshotelse{print("Error retreiving snapshot:\(error!)")return}fordiffinsnapshot.documentChanges{ifdiff.type==.added{print("New city:\(diff.document.data())")}}letsource=snapshot.metadata.isFromCache?"local cache":"server"print("Metadata: Data fetched from\(source)")}
ViewController.swift

// Listen to metadata updates to receive a server snapshot even if// the data is the same as the cached data.[[[dbcollectionWithPath:@"cities"]queryWhereField:@"state"isEqualTo:@"CA"]addSnapshotListenerWithIncludeMetadataChanges:YESlistener:^(FIRQuerySnapshot*snapshot,NSError*error){if(snapshot==nil){NSLog(@"Error retreiving snapshot: %@",error);return;}for(FIRDocumentChange*diffinsnapshot.documentChanges){if(diff.type==FIRDocumentChangeTypeAdded){NSLog(@"New city: %@",diff.document.data);}}NSString*source=snapshot.metadata.isFromCache?@"local cache":@"server";NSLog(@"Metadata: Data fetched from %@",source);}];
ViewController.m

db.collection("cities").whereEqualTo("state","CA").addSnapshotListener(MetadataChanges.INCLUDE){querySnapshot,e->if(e!=null){Log.w(TAG,"Listen error",e)return@addSnapshotListener}for(changeinquerySnapshot!!.documentChanges){if(change.type==DocumentChange.Type.ADDED){Log.d(TAG,"New city: ${change.document.data}")}valsource=if(querySnapshot.metadata.isFromCache){"local cache"}else{"server"}Log.d(TAG,"Data fetched from $source")}}
DocSnippets.kt

db.collection("cities").whereEqualTo("state","CA").addSnapshotListener(MetadataChanges.INCLUDE,newEventListener<QuerySnapshot>(){@OverridepublicvoidonEvent(@NullableQuerySnapshotquerySnapshot,@NullableFirebaseFirestoreExceptione){if(e!=null){Log.w(TAG,"Listen error",e);return;}for(DocumentChangechange:querySnapshot.getDocumentChanges()){if(change.getType()==Type.ADDED){Log.d(TAG,"New city:"+change.getDocument().getData());}Stringsource=querySnapshot.getMetadata().isFromCache()?"local cache":"server";Log.d(TAG,"Data fetched from "+source);}}});
DocSnippets.java

db.collection("cities").where("state",isEqualTo:"CA").snapshots(includeMetadataChanges:true).listen((querySnapshot){for(varchangeinquerySnapshot.docChanges){if(change.type==DocumentChangeType.added){finalsource=(querySnapshot.metadata.isFromCache)?"local cache":"server";print("Data fetched from$source}");}}});
firestore.dart

ifletindexManager=Firestore.firestore().persistentCacheIndexManager{// Indexing is disabled by defaultindexManager.enableIndexAutoCreation()}else{print("indexManager is nil")}

PersistentCacheIndexManager*indexManager=[FIRFirestorefirestore].persistentCacheIndexManager;if(indexManager){// Indexing is disabled by default[indexManagerenableIndexAutoCreation];}

// return type: PersistentCacheManager?Firebase.firestore.persistentCacheIndexManager?.apply{// Indexing is disabled by defaultenableIndexAutoCreation()}?:println("indexManager is null")

// return type: @Nullable PersistentCacheIndexManagerPersistentCacheIndexManagerindexManager=FirebaseFirestore.getInstance().getPersistentCacheIndexManager();if(indexManager!=null){// Indexing is disabled by defaultindexManager.enableIndexAutoCreation();}// If not check indexManager != null, IDE shows warning: Method invocation 'enableIndexAutoCreation' may produce 'NullPointerException'FirebaseFirestore.getInstance().getPersistentCacheIndexManager().enableIndexAutoCreation();

import{disableNetwork}from"firebase/firestore";awaitdisableNetwork(db);console.log("Network disabled!");// Do offline actions// ...
disable_network.js

firebase.firestore().disableNetwork().then(()=>{// Do offline actions// ...});
test.firestore.js

Firestore.firestore().disableNetwork{(error)in// Do offline things// ...}
ViewController.swift

[[FIRFirestorefirestore]disableNetworkWithCompletion:^(NSError*_Nullableerror){// Do offline actions// ...}];
ViewController.m

db.disableNetwork().addOnCompleteListener{// Do offline things// ...}
DocSnippets.kt

db.disableNetwork().addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){// Do offline things// ...}});
DocSnippets.java

db.disableNetwork().then((_){// Do offline things});
firestore.dart

import{enableNetwork}from"firebase/firestore";awaitenableNetwork(db);// Do online actions// ...
enable_network.js

firebase.firestore().enableNetwork().then(()=>{// Do online actions// ...});
test.firestore.js

Firestore.firestore().enableNetwork{(error)in// Do online things// ...}
ViewController.swift

[[FIRFirestorefirestore]enableNetworkWithCompletion:^(NSError*_Nullableerror){// Do online actions// ...}];
ViewController.m

db.enableNetwork().addOnCompleteListener{// Do online things// ...}
DocSnippets.kt

db.enableNetwork().addOnCompleteListener(newOnCompleteListener<Void>(){@OverridepublicvoidonComplete(@NonNullTask<Void>task){// Do online things// ...}});
DocSnippets.java

db.enableNetwork().then((_){// Back online});
firestore.dart