--- title: "default | JavaScript maps SDK" description: "Documentation for MapTiler SDK" --- > For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL. # Class default #### Type Parameters - KeyType - ValueType #### Hierarchy - Map<[KeyType](#keytype), [ValueType](#valuetype)\> - default #### Implements - [Iterable](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.Iterable/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\> ##### Index ### Constructors[](#constructors) [constructor](#constructor) ### Properties[](#properties) [\[toStringTag\]](#tostringtag) [\[species\]](#species) ### Accessors[](#accessors) [maxAge](#maxage) [maxSize](#maxsize) [size](#size) ### Methods[](#methods) [\[iterator\]](#iterator) [clear](#clear) [delete](#delete) [entries](#entries) [entriesAscending](#entriesascending) [entriesDescending](#entriesdescending) [evict](#evict) [expiresIn](#expiresin) [forEach](#foreach) [get](#get) [has](#has) [keys](#keys) [peek](#peek) [resize](#resize) [set](#set) [values](#values) ## Constructors[](#constructors-1) ### constructor[](#constructor) - new default<[KeyType](#constructordefaultkeytype), [ValueType](#constructordefaultvaluetype)\>(     options: [Options](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.Options/)<[KeyType](#keytype), [ValueType](#valuetype)\>, ): default<[KeyType](#keytype), [ValueType](#valuetype)\>[](#constructordefault) Simple ["Least Recently Used" (LRU) cache](https://en.m.wikipedia.org/wiki/Cache_replacement_policies#Least_Recently_Used_.28LRU.29). The instance is an [`Iterable`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Iteration_protocols) of `[key, value]` pairs so you can use it directly in a [`for…of`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Statements/for...of) loop. #### Type Parameters - KeyType - ValueType #### Parameters - options: [Options](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.Options/)<[KeyType](#keytype), [ValueType](#valuetype)\> #### Returns default<[KeyType](#keytype), [ValueType](#valuetype)\> #### Example[](#example) ```typescript import QuickLRU from 'quick-lru'; const lru = new QuickLRU({maxSize: 1000}); lru.set('🦄', '🌈'); lru.has('🦄'); //=> true lru.get('🦄'); //=> '🌈' ``` Overrides Map.constructor ## Properties[](#properties-1) ### `Readonly`\[toStringTag\][](#tostringtag) "\[toStringTag\]": string Inherited from Map.\[toStringTag\] ### `Static` `Readonly`\[species\][](#species) "\[species\]": MapConstructor Inherited from Map.\[species\] ## Accessors[](#accessors-1) ### maxAge[](#maxage) - get maxAge(): number The set max age. #### Returns number ### maxSize[](#maxsize) - get maxSize(): number The set max size. #### Returns number ### size[](#size) - get size(): number The stored item count. #### Returns number Overrides Map.size ## Methods[](#methods-1) ### \[iterator\][](#iterator) - "\[iterator\]"(): [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\>[](#iterator-1) #### Returns [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\> Implementation of [Iterable](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.Iterable/).[\[iterator\]](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.Iterable/#iterator) Overrides Map.\[iterator\] ### clear[](#clear) - clear(): void[](#clear-1) Delete all items. #### Returns void Overrides Map.clear ### delete[](#delete) - delete(key: [KeyType](#keytype)): boolean[](#delete-1) Delete an item. #### Parameters - key: [KeyType](#keytype) #### Returns boolean `true` if the item is removed or `false` if the item doesn't exist. Overrides Map.delete ### entries[](#entries) - entries(): [MapIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.MapIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\>[](#entries-1) Returns an iterable of key, value pairs for every entry in the map. #### Returns [MapIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.MapIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\> Inherited from Map.entries ### entriesAscending[](#entriesascending) - entriesAscending(): [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\>[](#entriesascending-1) Iterable for all entries, starting with the oldest (ascending in recency). #### Returns [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\> ### entriesDescending[](#entriesdescending) - entriesDescending(): [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\>[](#entriesdescending-1) Iterable for all entries, starting with the newest (descending in recency). #### Returns [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<\[[KeyType](#keytype), [ValueType](#valuetype)\]\> ### evict[](#evict) - evict(count?: number): void[](#evict-1) Evict the least recently used items from the cache. #### Parameters - `Optional`count: number The number of items to evict. Defaults to 1. It will always keep at least one item in the cache. #### Returns void #### Example[](#example-1) ```typescript import QuickLRU from 'quick-lru'; const lru = new QuickLRU({maxSize: 10}); lru.set('a', 1); lru.set('b', 2); lru.set('c', 3); lru.evict(2); // Evicts 'a' and 'b' console.log(lru.has('a')); //=> false console.log(lru.has('c')); //=> true ``` ### expiresIn[](#expiresin) - expiresIn(key: [KeyType](#keytype)): number | undefined[](#expiresin-1) Get the remaining time to live (in milliseconds) for the given item, or `undefined` when the item is not in the cache. - Does not mark the item as recently used. - Does not trigger lazy expiration or remove the entry when it is expired. - Returns `Infinity` if the item has no expiration. - May return a negative number if the item is already expired but not yet lazily removed. #### Parameters - key: [KeyType](#keytype) #### Returns number | undefined Remaining time to live in milliseconds when set, `Infinity` when there is no expiration, or `undefined` when the item does not exist. ### forEach[](#foreach) - forEach(     callbackfn: (         value: [ValueType](#valuetype),         key: [KeyType](#keytype),         map: Map<[KeyType](#keytype), [ValueType](#valuetype)\>,     ) \=> void,     thisArg?: any, ): void[](#foreach-1) Executes a provided function once per each key/value pair in the Map, in insertion order. #### Parameters - callbackfn: (value: [ValueType](#valuetype), key: [KeyType](#keytype), map: Map<[KeyType](#keytype), [ValueType](#valuetype)\>) \=> void - `Optional`thisArg: any #### Returns void Inherited from Map.forEach ### get[](#get) - get(key: [KeyType](#keytype)): [ValueType](#valuetype) | undefined[](#get-1) Get an item. #### Parameters - key: [KeyType](#keytype) #### Returns [ValueType](#valuetype) | undefined The stored item or `undefined`. Overrides Map.get ### has[](#has) - has(key: [KeyType](#keytype)): boolean[](#has-1) Check if an item exists. #### Parameters - key: [KeyType](#keytype) #### Returns boolean Overrides Map.has ### keys[](#keys) - keys(): [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<[KeyType](#keytype)\>[](#keys-1) Iterable for all the keys. #### Returns [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<[KeyType](#keytype)\> Overrides Map.keys ### peek[](#peek) - peek(key: [KeyType](#keytype)): [ValueType](#valuetype) | undefined[](#peek-1) Get an item without marking it as recently used. #### Parameters - key: [KeyType](#keytype) #### Returns [ValueType](#valuetype) | undefined The stored item or `undefined`. ### resize[](#resize) - resize(maxSize: number): void[](#resize-1) Update the `maxSize` in-place, discarding items as necessary. Insertion order is mostly preserved, though this is not a strong guarantee. Useful for on-the-fly tuning of cache sizes in live systems. #### Parameters - maxSize: number #### Returns void ### set[](#set) - set(key: [KeyType](#keytype), value: [ValueType](#valuetype), options?: { maxAge?: number }): this[](#set-1) Set an item. Returns the instance. Individual expiration of an item can be specified with the `maxAge` option. If not specified, the global `maxAge` value will be used in case it is specified in the constructor; otherwise the item will never expire. #### Parameters - key: [KeyType](#keytype) - value: [ValueType](#valuetype) - `Optional`options: { maxAge?: number } #### Returns this The cache instance. Overrides Map.set ### values[](#values) - values(): [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<[ValueType](#valuetype)\>[](#values-1) Iterable for all the values. #### Returns [IterableIterator](https://docs.maptiler.com/sdk-js/api-reference/interfaces/Externals.IterableIterator/)<[ValueType](#valuetype)\> Overrides Map.values