dreamstate/esm/development/core/signals/OnSignal.js

Store management library based on react context and observers

import { DreamstateError } from '../error/DreamstateError.js';
import { SIGNAL_METADATA_REGISTRY } from '../internals.js';
import { ContextManager } from '../management/ContextManager.js';
import { EDreamstateErrorCode } from '../../types/error.js';
import { createMethodDecorator } from '../../utils/polyfills/createMethodDecorator.js';
import { isCorrectSignalType } from '../../utils/typechecking.js';

/**
 * Class method decorator factory that marks the decorated method as a handler for specified signal types.
 *
 * This decorator ensures that the decorated method is invoked when a signal of the specified type(s)
 * is emitted within the current scope. It supports handling a single signal type or an array of signal types.
 *
 * Supported signal types include: `string`, `number`, and `symbol`.
 *
 * @param {(TSignalType | Array<TSignalType>)} signalType - The signal type or an array of signal types
 *   that the decorated method will handle.
 * @returns {MethodDecorator} A method decorator that attaches the handler functionality to the method.
 */
function OnSignal(signalType) {
  /*
   * If Array:
   *  - Check not empty
   *  - Validate all elements
   * If single type:
   *  - Check the only value
   */
  if (Array.isArray(signalType) ? signalType.length === 0 || signalType.some(function (it) {
    return !isCorrectSignalType(it);
  }) : !isCorrectSignalType(signalType)) {
    throw new DreamstateError(EDreamstateErrorCode.INCORRECT_PARAMETER, "Unexpected signal type provided, expected symbol, string, number or array of it. Got: ".concat(typeof signalType, "."));
  }
  /*
   * Support old and new decorators with polyfill.
   */
  return createMethodDecorator(function (method, ManagerClass) {
    if (!(ManagerClass.prototype instanceof ContextManager)) {
      throw new DreamstateError(EDreamstateErrorCode.INCORRECT_PARAMETER, "Only ContextManager extending classes methods can be decorated as handlers.");
    }
    if (SIGNAL_METADATA_REGISTRY.has(ManagerClass)) {
      SIGNAL_METADATA_REGISTRY.get(ManagerClass).push([method, signalType]);
    } else {
      SIGNAL_METADATA_REGISTRY.set(ManagerClass, [[method, signalType]]);
    }
  });
}

export { OnSignal };