add most.ts

Author: jcouyang

lib/engine/most.ts

@@ -0,0 +1,38 @@
+import { from, of, mergeArray, Stream, never, Subscription } from 'most'
+import { async as subject, AsyncSubject } from 'most-subject'
+
+export interface EngineSubject<T> extends AsyncSubject<T> {
+  send(x: T): this
+}
+
+export interface Update<S> {
+  (current: S): S
+}
+
+export class Engine<T, S> {
+  intentStream: EngineSubject<T>
+  historyStream: EngineSubject<S>
+  travelStream: EngineSubject<(n: number) => number>
+  constructor() {
+    this.intentStream = subject() as EngineSubject<T>
+    this.intentStream.send = this.intentStream.next.bind(this.intentStream)
+    this.historyStream = subject() as EngineSubject<S>
+    this.historyStream.send = this.historyStream.next.bind(this.historyStream)
+    this.travelStream = subject() as EngineSubject<(n: number) => number>;
+    this.travelStream.send = this.travelStream.next.bind(this.historyStream)
+  }
+
+  observe<T>(actionsSinks: Stream<Update<T>>[], f): Subscription<T> {
+    let subscriptions = mergeArray(actionsSinks)
+      .recoverWith(e => {
+        // console.error('There is Error in your reducer:', e, e.stack)
+        return of(x => x)
+      })
+      .subscribe({
+        next: f,
+        error: (e) => console.error('Something is Wrong:', e, e.stack),
+        complete: f
+      });
+    return subscriptions;
+  }
+}