DataLoader<K extends Object, V, C> class

A DataLoader creates a public API for loading data from a particular data back-end with unique keys such as the id column of a SQL table or document name in a MongoDB database, given a batch loading function.

Each DataLoader instance contains a unique memoized cache. Use caution when used in long-lived applications or those which serve many users with different access permissions and consider creating a new instance per web request.

Constructors

DataLoader(BatchLoadFn<K, V> _batchLoadFn, [DataLoaderOptions<K, V, C>? options])

Main DataLoader constructor use DataLoader.unmapped if the item key K is equal to the cache key C

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

clear(K key) → DataLoader<K, V, C>

Clears the value at key from the cache, if it exists. Returns itself for method chaining.

clearAll() → DataLoader<K, V, C>

Clears the entire cache. To be used when some event results in unknown invalidations across this particular DataLoader. Returns itself for method chaining.

load(K key) → Future<V>

Loads a key, returning a Future for the value represented by that key.

loadMany(List<K> keys) → Future<List<V>>

Loads multiple keys, promising an array of values:

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

prime(K key, V value) → DataLoader<K, V, C>

Adds the provided key and value to the cache. If the key already exists, no change is made. Returns itself for method chaining.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

unmapped<K extends Object, V>(BatchLoadFn<K, V> _batchLoadFn, [DataLoaderOptions<K, V, K>? options]) → DataLoader<K, V, K>

Constructs a DataLoader where the item key K is equal to the cache key