react-native-onyx/dist/StateMachine.js

State management for React Native

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * An immutable, type-safe finite state machine.
 * Pass the transition graph with `as const` so `transition` only accepts legal target states.
 *
 * @example
 * const transitions = {
 *     idle: ['loading'],
 *     loading: ['success', 'error'],
 *     success: [],
 *     error: ['idle'],
 * } as const;
 *
 * const idleMachine = new StateMachine('idle', transitions);
 * const loadingMachine = idleMachine.transition('loading');
 * loadingMachine.transition('success');
 */
class StateMachine {
    constructor(currentState, transitions) {
        this.state = currentState;
        this.transitions = transitions;
        Object.freeze(this);
    }
    /**
     * Transition to a new state, returning a new state machine instance.
     * Only transitions declared in the graph for the current state are accepted.
     */
    transition(target) {
        const validTargets = this.transitions[this.state];
        if (!(validTargets === null || validTargets === void 0 ? void 0 : validTargets.includes(target))) {
            throw new Error(`Illegal transition from "${String(this.state)}" to "${String(target)}"`);
        }
        return new StateMachine(target, this.transitions);
    }
}
exports.default = StateMachine;