[eff] Исправлена ошибка в обработке Chain

eff/index.ts

@@ -17,6 +17,8 @@ export type Eff<Error, Success> =
   | Apply<Error, Success>     // { args: Eff<unknown>[], proj(...args): Either<Error, Success> }
   | Chain<Error, Success>     // { first: Eff<unknown>, andThen(x: unknown): Eff<Error, Success> }
   | HasEffect<Error, Success> // { toEffect(): Eff<Error, Success> }
+  ;
+export type AnyEff = Eff<any, any>;
 
 
 // Instance methods for `Eff`
@@ -140,7 +142,7 @@ export function ap(): Eff<unknown, unknown> {
 }
 
 
-export function record<R extends Record<string, Eff<any, any>>>(rec: R): Eff<{ [K in keyof R]: R[K]['_Error'] }[keyof R], { [K in keyof R]: R[K]['_Success'] }> {
+export function record<R extends Record<string, AnyEff>>(rec: R): Eff<{ [K in keyof R]: R[K]['_Error'] }[keyof R], { [K in keyof R]: R[K]['_Success'] }> {
   const keys = Object.keys(rec);
   return ap.apply(undefined, [...keys.map(k => rec[k]), (...values) => values.reduce((acc, v, idx) => (acc[keys[idx]] = v, acc), {})]);
 }
@@ -240,23 +242,27 @@ export function go<Error, Success>(effect: Eff<Error, Success>, onNext: (x: Eith
   }
   
   if (effect instanceof Chain) {
-    const subscriptions: Array<Function|null> = [];
-    subscriptions.push(go(effect.first, result => {
-      const idx = subscriptions.length;
-      subscriptions.push(go(effect.andThen(result), onNext, () => {
-        subscriptions[idx] = null;
-        for (const unsub of subscriptions) if (unsub !== null) return;
-        onComplete();          
-      }));
-    }, () => {
-      subscriptions[0] = null;
-      for (const unsub of subscriptions) if (unsub !== null) return;
-      onComplete();
-    }));
+    const cancellers = new Map<AnyEff, Canceller>();
+    const handleEffect = (e: AnyEff) => {
+      const _onNext = result => {
+        if (e === effect.first) handleEffect(effect.andThen(result));
+        else onNext(result);
+      };
+      const _onComplete = () => {
+        if (!cancellers.has(e)) completedImmediately = true;
+        cancellers.delete(e);
+        if (cancellers.size === 0) onComplete();          
+      };
+      let completedImmediately = false;
       
-    return () => subscriptions.forEach(
-      funOrNull => funOrNull ? funOrNull() : void 0
-    );
+      const canceller = go(e, _onNext, _onComplete);
+      if (!completedImmediately) cancellers.set(e, canceller);
+    };
+
+    handleEffect(effect.first);
+    if (cancellers.size === 0) return noopFunc;
+    
+    return () => cancellers.forEach(canceller => canceller());
   }
   
   if (effect instanceof Apply) {
@@ -355,6 +361,9 @@ export abstract class HasEffect<Error, Success> extends EffBase<Error, Success>
 export const noop: Cmd<never> = new Batch([]);
 
 
+export type Canceller = () => void;
+
+
 export interface EffStatics {
   of: typeof of,
   success: typeof success,