80 lines
2.8 KiB
TypeScript
80 lines
2.8 KiB
TypeScript
import { useContext, useMemo } from 'react';
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import { UseBoundStoreWithEqualityFn, useStoreWithEqualityFn as useZustandStore } from 'zustand/traditional';
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import { StoreApi } from 'zustand';
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import { errorMessages } from '@xyflow/system';
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import StoreContext from '../contexts/StoreContext';
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import type { Edge, Node, ReactFlowState } from '../types';
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const zustandErrorMessage = errorMessages['error001']();
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/**
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* This hook can be used to subscribe to internal state changes of the React Flow
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* component. The `useStore` hook is re-exported from the [Zustand](https://github.com/pmndrs/zustand)
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* state management library, so you should check out their docs for more details.
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*
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* @public
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* @param selector - A selector function that returns a slice of the flow's internal state.
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* Extracting or transforming just the state you need is a good practice to avoid unnecessary
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* re-renders.
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* @param equalityFn - A function to compare the previous and next value. This is incredibly useful
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* for preventing unnecessary re-renders. Good sensible defaults are using `Object.is` or importing
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* `zustand/shallow`, but you can be as granular as you like.
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* @returns The selected state slice.
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*
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* @example
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* ```ts
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* const nodes = useStore((state) => state.nodes);
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* ```
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*
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* @remarks This hook should only be used if there is no other way to access the internal
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* state. For many of the common use cases, there are dedicated hooks available
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* such as {@link useReactFlow}, {@link useViewport}, etc.
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*/
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function useStore<StateSlice = unknown>(
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selector: (state: ReactFlowState) => StateSlice,
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equalityFn?: (a: StateSlice, b: StateSlice) => boolean
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) {
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const store = useContext(StoreContext);
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if (store === null) {
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throw new Error(zustandErrorMessage);
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}
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return useZustandStore(store, selector, equalityFn);
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}
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/**
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* In some cases, you might need to access the store directly. This hook returns the store object which can be used on demand to access the state or dispatch actions.
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*
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* @returns The store object.
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* @example
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* ```ts
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* const store = useStoreApi();
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* ```
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*
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* @remarks This hook should only be used if there is no other way to access the internal
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* state. For many of the common use cases, there are dedicated hooks available
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* such as {@link useReactFlow}, {@link useViewport}, etc.
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*/
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function useStoreApi<NodeType extends Node = Node, EdgeType extends Edge = Edge>() {
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const store = useContext(StoreContext) as UseBoundStoreWithEqualityFn<
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StoreApi<ReactFlowState<NodeType, EdgeType>>
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> | null;
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if (store === null) {
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throw new Error(zustandErrorMessage);
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}
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return useMemo(
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() => ({
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getState: store.getState,
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setState: store.setState,
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subscribe: store.subscribe,
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}),
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[store]
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);
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}
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export { useStore, useStoreApi };
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