haunted/lib/use-reducer.js

Hooks for web components

import { hook, Hook } from "./hook";
/**
 * Given a reducer function, initial state, and optional state initializer function, returns a tuple of state and dispatch function.
 * @function
 * @template S State
 * @template I Initial State
 * @template A Action
 * @param {Reducer<S, A>} reducer - reducer function to compute the next state given the previous state and the action
 * @param {I} initialState - the initial state of the reducer
 * @param {(init: I) => S} [init=undefined] - Optional initializer function, called on initialState if provided
 * @return {readonly [S, (action: A) => void]}
 */
const useReducer = hook(class extends Hook {
    reducer;
    currentState;
    constructor(id, state, _, initialState, init) {
        super(id, state);
        this.dispatch = this.dispatch.bind(this);
        this.currentState =
            init !== undefined ? init(initialState) : initialState;
    }
    update(reducer) {
        this.reducer = reducer;
        return [this.currentState, this.dispatch];
    }
    dispatch(action) {
        this.currentState = this.reducer(this.currentState, action);
        this.state.update();
    }
});
export { useReducer };