Defined in: packages/db/src/collection/index.ts:54
Enhanced Collection interface that includes both data type T and utilities TUtils
T extends object = Record<string, unknown>
The type of items in the collection
TKey extends string | number = string | number
The type of the key for the collection
TUtils extends UtilsRecord = UtilsRecord
The utilities record type
TSchema extends StandardSchemaV1 = StandardSchemaV1
TInsertInput extends object = T
The type for insert operations (can be different from T for schemas with defaults)
_lifecycle: CollectionLifecycleManager<T, TKey, TSchema, TInsertInput>;
Defined in: packages/db/src/collection/index.ts:289
_state: CollectionStateManager<T, TKey, TSchema, TInsertInput>;
Defined in: packages/db/src/collection/index.ts:301
_sync: CollectionSyncManager<T, TKey, TSchema, TInsertInput>;
Defined in: packages/db/src/collection/index.ts:290
config: CollectionConfig<T, TKey, TSchema>;
Defined in: packages/db/src/collection/index.ts:280
deferDataRefresh: Promise<void> | null = null;
Defined in: packages/db/src/collection/index.ts:308
When set, collection consumers should defer processing incoming data refreshes until this promise resolves. This prevents stale data from overwriting optimistic state while pending writes are being applied.
CollectionImpl.deferDataRefresh
id: string;
Defined in: packages/db/src/collection/index.ts:279
readonly optional singleResult: true;
Defined in: packages/db/src/collection/index.ts:62
readonly utils: TUtils;
Defined in: packages/db/src/collection/index.ts:61
get compareOptions(): StringCollationConfig;
Defined in: packages/db/src/collection/index.ts:643
get indexes(): Map<number, BaseIndex<TKey>>;
Defined in: packages/db/src/collection/index.ts:628
Get resolved indexes for query optimization
Map<number, BaseIndex<TKey>>
get isLoadingSubset(): boolean;
Defined in: packages/db/src/collection/index.ts:456
Check if the collection is currently loading more data
boolean
true if the collection has pending load more operations, false otherwise
CollectionImpl.isLoadingSubset
get size(): number;
Defined in: packages/db/src/collection/index.ts:493
Get the current size of the collection (cached)
number
get state(): Map<TKey, WithVirtualProps<TOutput, TKey>>;
Defined in: packages/db/src/collection/index.ts:820
Gets the current state of the collection as a Map
const itemsMap = collection.state
console.log(`Collection has ${itemsMap.size} items`)
for (const [key, item] of itemsMap) {
console.log(`${key}: ${item.title}`)
}
// Check if specific item exists
if (itemsMap.has("todo-1")) {
console.log("Todo 1 exists:", itemsMap.get("todo-1"))
}
Map<TKey, WithVirtualProps<TOutput, TKey>>
Map containing all items in the collection, with keys as identifiers
get status(): CollectionStatus;
Defined in: packages/db/src/collection/index.ts:411
Gets the current status of the collection
get subscriberCount(): number;
Defined in: packages/db/src/collection/index.ts:418
Get the number of subscribers to the collection
number
CollectionImpl.subscriberCount
get toArray(): WithVirtualProps<TOutput, TKey>[];
Defined in: packages/db/src/collection/index.ts:849
Gets the current state of the collection as an Array
WithVirtualProps<TOutput, TKey>[]
An Array containing all items in the collection
iterator: IterableIterator<[TKey, WithVirtualProps<T, TKey>]>;
Defined in: packages/db/src/collection/index.ts:531
Get all entries (virtual derived state)
IterableIterator<[TKey, WithVirtualProps<T, TKey>]>
cleanup(): Promise<void>;
Defined in: packages/db/src/collection/index.ts:988
Clean up the collection by stopping sync and clearing data This can be called manually or automatically by garbage collection
Promise<void>
createIndex<TIndexType>(indexCallback, config): BaseIndex<TKey>;
Defined in: packages/db/src/collection/index.ts:597
Creates an index on a collection for faster queries. Indexes significantly improve query performance by allowing constant time lookups and logarithmic time range queries instead of full scans.
TIndexType extends IndexConstructor<TKey>
(row) => any
Function that extracts the indexed value from each item
IndexOptions<TIndexType> = {}
Configuration including index type and type-specific options
BaseIndex<TKey>
The created index
import { BasicIndex } from '@tanstack/db'
// Create an index with explicit type
const ageIndex = collection.createIndex((row) => row.age, {
indexType: BasicIndex
})
// Create an index with collection's default type
const nameIndex = collection.createIndex((row) => row.name)
currentStateAsChanges(options):
| void
| ChangeMessage<WithVirtualProps<T, TKey>, string | number>[];
Defined in: packages/db/src/collection/index.ts:887
Returns the current state of the collection as an array of changes
CurrentStateAsChangesOptions = {}
Options including optional where filter
| void | ChangeMessage<WithVirtualProps<T, TKey>, string | number>[]
An array of changes
// Get all items as changes
const allChanges = collection.currentStateAsChanges()
// Get only items matching a condition
const activeChanges = collection.currentStateAsChanges({
where: (row) => row.status === 'active'
})
// Get only items using a pre-compiled expression
const activeChanges = collection.currentStateAsChanges({
whereExpression: eq(row.status, 'active')
})
CollectionImpl.currentStateAsChanges
delete(keys, config?): Transaction<any>;
Defined in: packages/db/src/collection/index.ts:797
Deletes one or more items from the collection
Single key or array of keys to delete
TKey | TKey[]
Optional configuration including metadata
Transaction<any>
A Transaction object representing the delete operation(s)
// Delete a single item
const tx = collection.delete("todo-1")
await tx.isPersisted.promise
// Delete multiple items
const tx = collection.delete(["todo-1", "todo-2"])
await tx.isPersisted.promise
// Delete with metadata
const tx = collection.delete("todo-1", { metadata: { reason: "completed" } })
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.delete("item-1")
await tx.isPersisted.promise
console.log('Delete successful')
} catch (error) {
console.log('Delete failed:', error)
}
entries(): IterableIterator<[TKey, WithVirtualProps<T, TKey>]>;
Defined in: packages/db/src/collection/index.ts:519
Get all entries (virtual derived state)
IterableIterator<[TKey, WithVirtualProps<T, TKey>]>
forEach(callbackfn): void;
Defined in: packages/db/src/collection/index.ts:540
Execute a callback for each entry in the collection
(value, key, index) => void
void
get(key):
| WithVirtualProps<T, TKey>
| undefined;
Defined in: packages/db/src/collection/index.ts:479
Get the current value for a key (virtual derived state)
TKey
| WithVirtualProps<T, TKey> | undefined
getIndexMetadata(): CollectionIndexMetadata[];
Defined in: packages/db/src/collection/index.ts:621
Returns a snapshot of current index metadata sorted by indexId. Persistence wrappers can use this to bootstrap index state if indexes were created before event listeners were attached.
CollectionImpl.getIndexMetadata
getKeyFromItem(item): TKey;
Defined in: packages/db/src/collection/index.ts:571
T
TKey
has(key): boolean;
Defined in: packages/db/src/collection/index.ts:486
Check if a key exists in the collection (virtual derived state)
TKey
boolean
insert(data, config?): Transaction<Record<string, unknown>>;
Defined in: packages/db/src/collection/index.ts:684
Inserts one or more items into the collection
TInsertInput | TInsertInput[]
Optional configuration including metadata
Transaction<Record<string, unknown>>
A Transaction object representing the insert operation(s)
If the data fails schema validation
// Insert a single todo (requires onInsert handler)
const tx = collection.insert({ id: "1", text: "Buy milk", completed: false })
await tx.isPersisted.promise
// Insert multiple todos at once
const tx = collection.insert([
{ id: "1", text: "Buy milk", completed: false },
{ id: "2", text: "Walk dog", completed: true }
])
await tx.isPersisted.promise
// Insert with metadata
const tx = collection.insert({ id: "1", text: "Buy groceries" },
{ metadata: { source: "mobile-app" } }
)
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.insert({ id: "1", text: "New item" })
await tx.isPersisted.promise
console.log('Insert successful')
} catch (error) {
console.log('Insert failed:', error)
}
isReady(): boolean;
Defined in: packages/db/src/collection/index.ts:448
Check if the collection is ready for use Returns true if the collection has been marked as ready by its sync implementation
boolean
true if the collection is ready, false otherwise
if (collection.isReady()) {
console.log('Collection is ready, data is available')
// Safe to access collection.state
} else {
console.log('Collection is still loading')
}
keys(): IterableIterator<TKey>;
Defined in: packages/db/src/collection/index.ts:500
Get all keys (virtual derived state)
IterableIterator<TKey>
map<U>(callbackfn): U[];
Defined in: packages/db/src/collection/index.ts:556
Create a new array with the results of calling a function for each entry in the collection
U
(value, key, index) => U
U[]
off<T>(event, callback): void;
Defined in: packages/db/src/collection/index.ts:967
Unsubscribe from a collection event
T extends | "status:error" | "status:idle" | "status:loading" | "status:ready" | "status:cleaned-up" | "status:change" | "subscribers:change" | "loadingSubset:change" | "truncate" | "index:added" | "index:removed"
T
CollectionEventHandler<T>
void
on<T>(event, callback): () => void;
Defined in: packages/db/src/collection/index.ts:947
Subscribe to a collection event
T extends | "status:error" | "status:idle" | "status:loading" | "status:ready" | "status:cleaned-up" | "status:change" | "subscribers:change" | "loadingSubset:change" | "truncate" | "index:added" | "index:removed"
T
CollectionEventHandler<T>
(): void;
void
once<T>(event, callback): () => void;
Defined in: packages/db/src/collection/index.ts:957
Subscribe to a collection event once
T extends | "status:error" | "status:idle" | "status:loading" | "status:ready" | "status:cleaned-up" | "status:change" | "subscribers:change" | "loadingSubset:change" | "truncate" | "index:added" | "index:removed"
T
CollectionEventHandler<T>
(): void;
void
onFirstReady(callback): void;
Defined in: packages/db/src/collection/index.ts:432
Register a callback to be executed when the collection first becomes ready Useful for preloading collections
() => void
Function to call when the collection first becomes ready
void
collection.onFirstReady(() => {
console.log('Collection is ready for the first time')
// Safe to access collection.state now
})
preload(): Promise<void>;
Defined in: packages/db/src/collection/index.ts:472
Preload the collection data by starting sync if not already started Multiple concurrent calls will share the same promise
Promise<void>
removeIndex(indexOrId): boolean;
Defined in: packages/db/src/collection/index.ts:612
Removes an index created with createIndex. Returns true when an index existed and was removed.
Best-effort semantics: removing an index guarantees it is detached from collection query planning. Existing index proxy references should be treated as invalid after removal.
number | BaseIndex<TKey>
boolean
startSyncImmediate(): void;
Defined in: packages/db/src/collection/index.ts:464
Start sync immediately - internal method for compiled queries This bypasses lazy loading for special cases like live query results
void
CollectionImpl.startSyncImmediate
stateWhenReady(): Promise<Map<TKey, WithVirtualProps<T, TKey>>>;
Defined in: packages/db/src/collection/index.ts:834
Gets the current state of the collection as a Map, but only resolves when data is available Waits for the first sync commit to complete before resolving
Promise<Map<TKey, WithVirtualProps<T, TKey>>>
Promise that resolves to a Map containing all items in the collection
subscribeChanges(callback, options): CollectionSubscription;
Defined in: packages/db/src/collection/index.ts:935
Subscribe to changes in the collection
(changes) => void
Function called when items change
SubscribeChangesOptions<T, TKey> = {}
Subscription options including includeInitialState and where filter
CollectionSubscription
Unsubscribe function - Call this to stop listening for changes
// Basic subscription
const subscription = collection.subscribeChanges((changes) => {
changes.forEach(change => {
console.log(`${change.type}: ${change.key}`, change.value)
})
})
// Later: subscription.unsubscribe()
// Include current state immediately
const subscription = collection.subscribeChanges((changes) => {
updateUI(changes)
}, { includeInitialState: true })
// Subscribe only to changes matching a condition using where callback
import { eq } from "@tanstack/db"
const subscription = collection.subscribeChanges((changes) => {
updateUI(changes)
}, {
includeInitialState: true,
where: (row) => eq(row.status, "active")
})
// Using multiple conditions with and()
import { and, eq, gt } from "@tanstack/db"
const subscription = collection.subscribeChanges((changes) => {
updateUI(changes)
}, {
where: (row) => and(eq(row.status, "active"), gt(row.priority, 5))
})
CollectionImpl.subscribeChanges
toArrayWhenReady(): Promise<WithVirtualProps<T, TKey>[]>;
Defined in: packages/db/src/collection/index.ts:859
Gets the current state of the collection as an Array, but only resolves when data is available Waits for the first sync commit to complete before resolving
Promise<WithVirtualProps<T, TKey>[]>
Promise that resolves to an Array containing all items in the collection
CollectionImpl.toArrayWhenReady
update(key, callback): Transaction;
Defined in: packages/db/src/collection/index.ts:729
Updates one or more items in the collection using a callback function
unknown[]
(drafts) => void
A Transaction object representing the update operation(s)
If the updated data fails schema validation
// Update single item by key
const tx = collection.update("todo-1", (draft) => {
draft.completed = true
})
await tx.isPersisted.promise
// Update multiple items
const tx = collection.update(["todo-1", "todo-2"], (drafts) => {
drafts.forEach(draft => { draft.completed = true })
})
await tx.isPersisted.promise
// Update with metadata
const tx = collection.update("todo-1",
{ metadata: { reason: "user update" } },
(draft) => { draft.text = "Updated text" }
)
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.update("item-1", draft => { draft.value = "new" })
await tx.isPersisted.promise
console.log('Update successful')
} catch (error) {
console.log('Update failed:', error)
}
update(
keys,
config,
callback): Transaction;
Defined in: packages/db/src/collection/index.ts:735
Updates one or more items in the collection using a callback function
unknown[]
Single key or array of keys to update
(drafts) => void
A Transaction object representing the update operation(s)
If the updated data fails schema validation
// Update single item by key
const tx = collection.update("todo-1", (draft) => {
draft.completed = true
})
await tx.isPersisted.promise
// Update multiple items
const tx = collection.update(["todo-1", "todo-2"], (drafts) => {
drafts.forEach(draft => { draft.completed = true })
})
await tx.isPersisted.promise
// Update with metadata
const tx = collection.update("todo-1",
{ metadata: { reason: "user update" } },
(draft) => { draft.text = "Updated text" }
)
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.update("item-1", draft => { draft.value = "new" })
await tx.isPersisted.promise
console.log('Update successful')
} catch (error) {
console.log('Update failed:', error)
}
update(id, callback): Transaction;
Defined in: packages/db/src/collection/index.ts:742
Updates one or more items in the collection using a callback function
unknown
(draft) => void
A Transaction object representing the update operation(s)
If the updated data fails schema validation
// Update single item by key
const tx = collection.update("todo-1", (draft) => {
draft.completed = true
})
await tx.isPersisted.promise
// Update multiple items
const tx = collection.update(["todo-1", "todo-2"], (drafts) => {
drafts.forEach(draft => { draft.completed = true })
})
await tx.isPersisted.promise
// Update with metadata
const tx = collection.update("todo-1",
{ metadata: { reason: "user update" } },
(draft) => { draft.text = "Updated text" }
)
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.update("item-1", draft => { draft.value = "new" })
await tx.isPersisted.promise
console.log('Update successful')
} catch (error) {
console.log('Update failed:', error)
}
update(
id,
config,
callback): Transaction;
Defined in: packages/db/src/collection/index.ts:748
Updates one or more items in the collection using a callback function
unknown
(draft) => void
A Transaction object representing the update operation(s)
If the updated data fails schema validation
// Update single item by key
const tx = collection.update("todo-1", (draft) => {
draft.completed = true
})
await tx.isPersisted.promise
// Update multiple items
const tx = collection.update(["todo-1", "todo-2"], (drafts) => {
drafts.forEach(draft => { draft.completed = true })
})
await tx.isPersisted.promise
// Update with metadata
const tx = collection.update("todo-1",
{ metadata: { reason: "user update" } },
(draft) => { draft.text = "Updated text" }
)
await tx.isPersisted.promise
// Handle errors
try {
const tx = collection.update("item-1", draft => { draft.value = "new" })
await tx.isPersisted.promise
console.log('Update successful')
} catch (error) {
console.log('Update failed:', error)
}
validateData(
data,
type,
key?): T;
Defined in: packages/db/src/collection/index.ts:635
Validates the data against the schema
unknown
"insert" | "update"
TKey
T
values(): IterableIterator<WithVirtualProps<T, TKey>>;
Defined in: packages/db/src/collection/index.ts:507
Get all values (virtual derived state)
IterableIterator<WithVirtualProps<T, TKey>>
waitFor<T>(event, timeout?): Promise<AllCollectionEvents[T]>;
Defined in: packages/db/src/collection/index.ts:977
Wait for a collection event
T extends | "status:error" | "status:idle" | "status:loading" | "status:ready" | "status:cleaned-up" | "status:change" | "subscribers:change" | "loadingSubset:change" | "truncate" | "index:added" | "index:removed"
T
number
Promise<AllCollectionEvents[T]>