@felangel/bloc
Version:
A predictable state management library that helps implement the BLoC design pattern in JavaScript
273 lines • 12 kB
JavaScript
;
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
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function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
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function verb(n) { return function (v) { return step([n, v]); }; }
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var __asyncValues = (this && this.__asyncValues) || function (o) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var m = o[Symbol.asyncIterator], i;
return m ? m.call(o) : (o = typeof __values === "function" ? __values(o) : o[Symbol.iterator](), i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i);
function verb(n) { i[n] = o[n] && function (v) { return new Promise(function (resolve, reject) { v = o[n](v), settle(resolve, reject, v.done, v.value); }); }; }
function settle(resolve, reject, d, v) { Promise.resolve(v).then(function(v) { resolve({ value: v, done: d }); }, reject); }
};
Object.defineProperty(exports, "__esModule", { value: true });
var rxjs_1 = require("rxjs");
var operators_1 = require("rxjs/operators");
var bloc_1 = require("../bloc");
var Bloc = /** @class */ (function (_super) {
__extends(Bloc, _super);
function Bloc(_state) {
var _this = _super.call(this) || this;
_this._state = _state;
_this.emitted = false;
_this.eventSubject = new rxjs_1.Subject();
_this.transitionSubscription = rxjs_1.Subscription.EMPTY;
_this.stateSubject = new rxjs_1.Subject();
_this.bindStateSubject();
return _this;
}
Object.defineProperty(Bloc.prototype, "state", {
/**
* Returns the current state of the bloc.
*
* @readonly
* @type {State}
* @memberof Bloc
*/
get: function () {
return this._state;
},
enumerable: true,
configurable: true
});
/**
* Adds a Subscription to the bloc's state stream.
*
* @param {(value: State) => void} onData
* @param {(((onError: any) => any) | undefined)} [onError]
* @param {((() => any) | undefined)} [onDone]
* @return {*} {Subscription}
* @memberof Bloc
*/
Bloc.prototype.listen = function (onData, onError, onDone) {
return this.stateSubject.subscribe(onData, onError, onDone);
};
/**
* Notifies the bloc of a new event which triggers `mapEventToState`.
*
* @param {Event} event
* @memberof Bloc
*/
Bloc.prototype.add = function (event) {
try {
if (this.eventSubject.isStopped) {
throw new bloc_1.EventStreamClosedError();
}
this.onEvent(event);
this.eventSubject.next(event);
}
catch (error) {
this.onError(error);
}
};
/**
* Called whenever an event is added to the bloc.
*
* @param {Event} event
* @memberof Bloc
*/
Bloc.prototype.onEvent = function (event) {
Bloc.observer.onEvent(this, event);
};
/**
* Transforms the events along with a `NextFunction` into
* an `Observable<Transition>`.
* Events that should be processed by `mapEventToState` need to be passed to
* the `next`.
* By default `concatMap` is used to ensure all events are processed in
* the order in which they are received.
* You can override `transformEvents` for advanced usage in order to
* manipulate the frequency and specificity with which `mapEventToState` is
* called as well as which `events` are processed.
*
* @param {Observable<Event>} events
* @param {NextFunction<Event, State>} next
* @return {*} {Observable<Transition<Event, State>>}
* @memberof Bloc
*/
Bloc.prototype.transformEvents = function (events, next) {
return events.pipe(operators_1.concatMap(next));
};
/**
* Transforms the `Observable<Transition>` into a new `Observable<Transition>`.
* By default `transformTransitions` returns the incoming `Observable<Transition>`.
* You can override `transformTransitions` for advanced usage in order to
* manipulate the frequency and specificity at which `transitions`
* (state changes) occur.
*
* @param {Observable<Transition<Event, State>>} transitions
* @return {*} {Observable<Transition<Event, State>>}
* @memberof Bloc
*/
Bloc.prototype.transformTransitions = function (transitions) {
return transitions;
};
/**
* Called whenever a `transition` occurs with the given `transition`.
* A `transition` occurs when a new `event` is added and `mapEventToState` executed.
* `onTransition` is called before a bloc's state has been updated.
*
* @param {Transition<Event, State>} transition
* @memberof Bloc
*/
Bloc.prototype.onTransition = function (transition) {
Bloc.observer.onTransition(this, transition);
};
/**
* Called whenever an `error` is thrown within `mapEventToState`.
* By default all errors will be ignored and bloc functionality will be unaffected.
*
* @param {*} error
* @memberof Bloc
*/
Bloc.prototype.onError = function (error) {
Bloc.observer.onError(this, error);
};
/**
* This method should be called when a `Bloc` is no longer needed.
* Disposes the resources held by the bloc which means the `Bloc` will
* no longer process new events after `close` has been called.
*
* @memberof Bloc
*/
Bloc.prototype.close = function () {
this.stateSubject.complete();
this.eventSubject.complete();
this.transitionSubscription.unsubscribe();
};
Bloc.prototype.bindStateSubject = function () {
var _this = this;
this.transitionSubscription = this.transformTransitions(this.transformEvents(this.eventSubject, function (event) {
return asyncToObservable(_this.mapEventToState(event)).pipe(operators_1.map(function (nextState, _) {
return new bloc_1.Transition(_this.state, event, nextState);
}), operators_1.catchError(function (error) {
_this.onError(error);
return rxjs_1.EMPTY;
}));
})).subscribe(function (transition) {
if (transition.nextState == _this.state && _this.emitted)
return;
try {
_this.onTransition(transition);
_this._state = transition.nextState;
_this.stateSubject.next(transition.nextState);
}
catch (error) {
_this.onError(error);
}
_this.emitted = true;
});
};
Bloc.observer = new bloc_1.BlocObserver();
return Bloc;
}(rxjs_1.Observable));
exports.Bloc = Bloc;
function asyncToObservable(iterable) {
var _this = this;
return new rxjs_1.Observable(function (observer) {
return void (function () { return __awaiter(_this, void 0, void 0, function () {
var iterable_1, iterable_1_1, item, e_1_1, e_2;
var e_1, _a;
return __generator(this, function (_b) {
switch (_b.label) {
case 0:
_b.trys.push([0, 13, , 14]);
_b.label = 1;
case 1:
_b.trys.push([1, 6, 7, 12]);
iterable_1 = __asyncValues(iterable);
_b.label = 2;
case 2: return [4 /*yield*/, iterable_1.next()];
case 3:
if (!(iterable_1_1 = _b.sent(), !iterable_1_1.done)) return [3 /*break*/, 5];
item = iterable_1_1.value;
if (observer.closed)
return [2 /*return*/];
observer.next(item);
_b.label = 4;
case 4: return [3 /*break*/, 2];
case 5: return [3 /*break*/, 12];
case 6:
e_1_1 = _b.sent();
e_1 = { error: e_1_1 };
return [3 /*break*/, 12];
case 7:
_b.trys.push([7, , 10, 11]);
if (!(iterable_1_1 && !iterable_1_1.done && (_a = iterable_1.return))) return [3 /*break*/, 9];
return [4 /*yield*/, _a.call(iterable_1)];
case 8:
_b.sent();
_b.label = 9;
case 9: return [3 /*break*/, 11];
case 10:
if (e_1) throw e_1.error;
return [7 /*endfinally*/];
case 11: return [7 /*endfinally*/];
case 12:
observer.complete();
return [3 /*break*/, 14];
case 13:
e_2 = _b.sent();
observer.error(e_2);
return [3 /*break*/, 14];
case 14: return [2 /*return*/];
}
});
}); })();
});
}
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