smartstate/ts/smartstate.classes.statepart.ts

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import * as plugins from './smartstate.plugins';
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import { StateAction, IActionDef } from './smartstate.classes.stateaction';
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export class StatePart<TStatePartName, TStatePayload> {
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public name: TStatePartName;
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public state = new plugins.smartrx.rxjs.Subject<TStatePayload>();
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public stateStore: TStatePayload;
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constructor(nameArg: TStatePartName) {
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this.name = nameArg;
}
/**
* gets the state from the state store
*/
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public getState(): TStatePayload {
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return this.stateStore;
}
/**
* sets the stateStore to the new state
* @param newStateArg
*/
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public setState(newStateArg: TStatePayload) {
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this.stateStore = newStateArg;
this.notifyChange();
}
/**
* notifies of a change on the state
*/
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public notifyChange() {
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this.state.next(this.stateStore);
}
/**
* selects a state or a substate
*/
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public select<T = TStatePayload>(
selectorFn?: (state: TStatePayload) => T
): plugins.smartrx.rxjs.Observable<T> {
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if (!selectorFn) {
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selectorFn = (state: TStatePayload) => <T>(<any>state);
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}
const mapped = this.state.pipe(
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plugins.smartrx.rxjs.ops.startWith(this.getState()),
plugins.smartrx.rxjs.ops.map(stateArg => {
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try {
return selectorFn(stateArg);
} catch (e) {
// Nothing here
}
})
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);
return mapped;
}
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/**
* creates an action capable of modifying the state
*/
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public createAction<TActionPayload>(
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actionDef: IActionDef<TStatePayload, TActionPayload>
): StateAction<TStatePayload, TActionPayload> {
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return new StateAction(this, actionDef);
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}
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/**
* dispatches an action on the statepart level
*/
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public async dispatchAction<T>(stateAction: StateAction<TStatePayload, T>, actionPayload: T) {
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const newState = await stateAction.actionDef(this, actionPayload);
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this.setState(newState);
}
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/**
* waits until a certain part of the state becomes available
* @param selectorFn
*/
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public async waitUntilPresent<T = TStatePayload>(
selectorFn?: (state: TStatePayload) => T
): Promise<T> {
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const done = plugins.smartpromise.defer<T>();
const selectedObservable = this.select(selectorFn);
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const subscription = selectedObservable.subscribe(async value => {
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if (value) {
done.resolve(value);
}
});
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const result = await done.promise;
subscription.unsubscribe();
return result;
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}
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}