Packages > @fluidframework/map > SharedMap
SharedMap Class
The SharedMap distributed data structure can be used to store key-value pairs. It provides the same API for setting and retrieving values that JavaScript developers are accustomed to with the Map built-in object. However, the keys of a SharedMap must be strings.
Signature
export declare class SharedMap extends SharedObject<ISharedMapEvents> implements ISharedMap
Extends: SharedObject <ISharedMapEvents
Implements: ISharedMap
Constructors
| Constructor | Description |
|---|---|
| (constructor)(id, runtime, attributes) | Do not call the constructor. Instead, you should use the create method. |
Static Methods
| Method | Return Type | Description |
|---|---|---|
| create(runtime, id) | SharedMap | Create a new shared map. |
| getFactory() | IChannelFactory | Get a factory for SharedMap to register with the data store. |
Properties
| Property | Type | Description |
|---|---|---|
| [Symbol.toStringTag] | string | String representation for the class. |
| size | number | The number of key/value pairs stored in the map. |
Methods
| Method | Return Type | Description |
|---|---|---|
| [Symbol.iterator]() | IterableIterator<[string, any]> | Get an iterator over the entries in this map. |
| clear() | void | Clear all data from the map. |
| delete(key) | boolean | Delete a key from the map. |
| entries() | IterableIterator<[string, any]> | Get an iterator over the entries in this map. |
| forEach(callbackFn) | void | Executes the given callback on each entry in the map. |
| get(key) | T | undefined | Retrieves the given key from the map. |
| has(key) | boolean | Check if a key exists in the map. |
| keys() | IterableIterator<string> | Get an iterator over the keys in this map. |
| set(key, value) | this | Sets the value stored at key to the provided value. |
| values() | IterableIterator<any> | Get an iterator over the values in this map. |
Constructor Details
(constructor)
Do not call the constructor. Instead, you should use the create method .
Signature
constructor(id: string, runtime: IFluidDataStoreRuntime, attributes: IChannelAttributes);
Parameters
| Parameter | Type | Description |
|---|---|---|
| id | string | String identifier. |
| runtime | IFluidDataStoreRuntime | Data store runtime. |
| attributes | IChannelAttributes | The attributes for the map. |
Property Details
[Symbol.toStringTag]
String representation for the class.
Signature
readonly [Symbol.toStringTag]: string;
Type: string
size
The number of key/value pairs stored in the map.
Signature
get size(): number;
Type: number
Method Details
[Symbol.iterator]
Get an iterator over the entries in this map.
Signature
[Symbol.iterator](): IterableIterator<[string, any]>;
Returns
The iterator
Return type: IterableIterator<[string, any]>
clear
Clear all data from the map.
Signature
clear(): void;
create
Create a new shared map.
Signature
static create(runtime: IFluidDataStoreRuntime, id?: string): SharedMap;
Example
To create a SharedMap, call the static create method:
const myMap = SharedMap.create(this.runtime, id);
Parameters
| Parameter | Modifiers | Type | Description |
|---|---|---|---|
| runtime | IFluidDataStoreRuntime | The data store runtime that the new shared map belongs to. | |
| id | optional | string | Optional name of the shared map. |
Returns
Newly created shared map.
Return type: SharedMap
delete
Delete a key from the map.
Signature
delete(key: string): boolean;
Parameters
| Parameter | Type | Description |
|---|---|---|
| key | string | Key to delete |
Returns
True if the key existed and was deleted, false if it did not exist
Return type: boolean
entries
Get an iterator over the entries in this map.
Signature
entries(): IterableIterator<[string, any]>;
Returns
The iterator
Return type: IterableIterator<[string, any]>
forEach
Executes the given callback on each entry in the map.
Signature
forEach(callbackFn: (value: any, key: string, map: Map<string, any>) => void): void;
Parameters
| Parameter | Type | Description |
|---|---|---|
| callbackFn | (value: any, key: string, map: Map<string, any>) => void | Callback function |
get
Retrieves the given key from the map.
Signature
get<T = any>(key: string): T | undefined;
Type Parameters
| Parameter | Default | Description |
|---|---|---|
| T | any |
Parameters
| Parameter | Type | Description |
|---|---|---|
| key | string | Key to retrieve from |
Returns
The stored value, or undefined if the key is not set
Return type: T | undefined
getFactory
Get a factory for SharedMap to register with the data store.
Signature
static getFactory(): IChannelFactory;
Returns
A factory that creates SharedMaps and loads them from storage.
Return type: IChannelFactory
has
Check if a key exists in the map.
Signature
has(key: string): boolean;
Parameters
| Parameter | Type | Description |
|---|---|---|
| key | string | The key to check |
Returns
True if the key exists, false otherwise
Return type: boolean
keys
Get an iterator over the keys in this map.
Signature
keys(): IterableIterator<string>;
Returns
The iterator
Return type: IterableIterator<string>
set
Sets the value stored at key to the provided value.
Signature
set(key: string, value: any): this;
Parameters
| Parameter | Type | Description |
|---|---|---|
| key | string | Key to set at |
| value | any | Value to set |
Returns
The ISharedMap itself
Return type: this
values
Get an iterator over the values in this map.
Signature
values(): IterableIterator<any>;
Returns
The iterator
Return type: IterableIterator<any>