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Context APIs ​

The Context APIs provide a dependency injection mechanism, allowing you to share data throughout your application without prop drilling. A context is a reactive Map that can be used to store and retrieve values by key.

Core Context Functions ​

These functions form the core of Anchor's context system, allowing you to create and work with contexts.

createContext() ​

Creates a new, empty context.

typescript
type createContext = <K extends KeyLike, V>(init?: [K, V][]) => Map<K, V>;
  • init (optional): An array of key-value pairs to initialize the context with. See KeyLike.
  • Returns: A new Map instance that serves as the context.

withinContext() ​

Executes a function within a specific context. Any calls to getContext() or setContext() inside this function will read from or write to the provided context.

typescript
type withinContext = <K extends KeyLike, V, T>(context: Map<K, V>, fn: () => T) => T;
  • context: The context to activate for the duration of the function call.
  • fn: The function to execute.
  • Returns: The return value of the executed function.

getContext() ​

Retrieves a value from the currently active context.

typescript
type getContext = <V, K extends KeyLike = KeyLike>(key: K) => V | undefined;
  • key: The key of the value to retrieve. See KeyLike.
  • Returns: The value associated with the key, or undefined if the key is not found or if no context is active.

setContext() ​

Sets a value in the currently active context.

typescript
type setContext = <V, K extends KeyLike = KeyLike>(key: K, value: V) => void;
  • key: The key for the value being set. See KeyLike.
  • value: The value to set.

Context Management Functions ​

These functions provide manual control over the active context. In most cases, withinContext() is preferred.

activateContext() ​

Manually activates a context.

typescript
type activateContext = <K extends KeyLike, V>(context: Context<K, V>) => () => void;
  • context: The context to make active. See Context.
  • Returns: A restore function that, when called, deactivates the context and restores the previously active one.

getActiveContext() ​

Gets the currently active context.

typescript
type getActiveContext = () => Context<KeyLike, unknown> | undefined;
  • Returns: The active Context map, or undefined.

Global Context Functions ​

Anchor can maintain a single global context, which is useful in browser environments.

activateGlobalContext() ​

Creates and activates a new context that is globally available. Does nothing if a global context is already active or if run outside a browser.

typescript
type activateGlobalContext = () => void;

deactivateGlobalContext() ​

Deactivates and clears the global context.

typescript
type deactivateGlobalContext = () => void;