[update] Добавлен prepareUpdate

update/example/index.tsx

@@ -6,6 +6,8 @@ import * as http from '../../http';
 import { InputHTMLAttributes } from 'react';
 
 
+type Err = http.HttpError;
+
 type Props = {
 };
 
@@ -15,10 +17,10 @@ type State = {
   response?: http.Response;
 };
 
-const U = Update.bind<State>();
+const U = Update.bind<Err, State>();
 
 
-class Widget extends Update.Component<Props, State> {
+class Widget extends Update.Component<Err, Props, State> {
   state: State = { search: '', pending: false };
   
   handleNameChange: InputHTMLAttributes<HTMLInputElement>['onChange'] = (e) => this.setState({ search: e.target.value });

update/index.ts

@@ -102,7 +102,7 @@ export function go<Error, State, A>(
   
   if (update instanceof Apply) {
     let allInitialized = false;
-    let subscriptions: Array<Function|undefined|null> = new Array(update.args.length);
+    let cancellers: Array<Canceller|undefined|null> = new Array(update.args.length);
     const initializedFlags: Array<true|undefined> = new Array(update.args.length);
     const recentValues: unknown[] = new Array(update.args.length);
     const next = idx => result => {
@@ -116,46 +116,42 @@ export function go<Error, State, A>(
       onNext(update.proj.apply(void 0, recentValues));
     };
     const complete = idx => () => {
-      subscriptions[idx] = null;
-      for (const unsub of subscriptions) if (unsub !== null) return;
+      cancellers[idx] = null;
+      for (const c of cancellers) if (c !== null) return;
       onComplete();
     };      
 
     update.args.forEach((u, idx) => {
       const canceller = go(u, getState, setState, next(idx), onError, complete(idx));
-      if (subscriptions[idx] !== null) subscriptions[idx] = canceller;
+      if (cancellers[idx] !== null) cancellers[idx] = canceller;
     });
 
-    return () => subscriptions.forEach(
-      funOrNull => funOrNull ? funOrNull() : void 0
-    );
+    return () => cancellers.forEach(canceller => canceller ? canceller() : void 0);
   }
   
   if (update instanceof Batch) {
     if (update.steps.length === 0) { onNext(void 0 as any); onComplete(); return noopFunc; }
-    let subscriptions: Array<Function|null>;
+    let cancellers: Array<Canceller|null>;
     const loop = idx => () => {
-      subscriptions[idx] = null;
-      for (const unsub of subscriptions) if (unsub !== null) return;
+      cancellers[idx] = null;
+      for (const unsub of cancellers) if (unsub !== null) return;
       onNext(void 0 as any);
       onComplete(); // If control flow reaches here, that means all nested commands are completed
     };
-    subscriptions = update.steps.map((u, idx) => go(u, getState, setState, noopFunc, onError, loop(idx)));
+    cancellers = update.steps.map((u, idx) => go(u, getState, setState, noopFunc, onError, loop(idx)));
     
-    return () => subscriptions.forEach(
-      funOrNull => funOrNull ? funOrNull() : void 0
-    );
+    return () => cancellers.forEach(canceller => canceller ? canceller() : void 0);
   }
 
   if (update instanceof Concat) {
-    let unsubscribe: Function|null = null;
+    let canceller: Canceller|null = null;
     const loop = idx => () => {
       // If condition holds, then all nested effects are completed, therefore we're done
       if (idx >= update.steps.length) { onNext(void 0 as any); onComplete(); return; }
-      unsubscribe = go(update.steps[idx], getState, setState, noopFunc, onError, loop(idx + 1));
+      canceller = go(update.steps[idx], getState, setState, noopFunc, onError, loop(idx + 1));
     };
     loop(0);
-    return () => unsubscribe ? unsubscribe() : void 0;
+    return () => canceller ? canceller() : void 0;
   }
 
   if (update instanceof Difference) {
@@ -399,10 +395,11 @@ export class Component<Error, Props, State> extends React.Component<Props, State
   setState(updateOrProjOrPatch, callback?) {
     if (updateOrProjOrPatch instanceof UpdateBase) {
       const onUpdate = this.props['onUpdate'] as unknown;
+      const update = this.prepareUpdate(updateOrProjOrPatch);
       if (typeof(onUpdate) === 'function') {
-        onUpdate(updateOrProjOrPatch);
+        onUpdate(update);
       } else {
-        updateOrProjOrPatch.run(this, callback);
+        update.run(this, callback);
       }
       return;
     }
@@ -413,6 +410,10 @@ export class Component<Error, Props, State> extends React.Component<Props, State
       return this.setState(new Patch<Error, State, void>(updateOrProjOrPatch, callback))
     }
   }
+
+  prepareUpdate<A>(update: Update<Error, State, A>): Update<Error, State, A> {
+    return update;
+  }
 }
 
 export interface UpdateStatic {
@@ -426,6 +427,7 @@ export interface UpdateStatic {
   concat: typeof concat,
   Component: typeof Component,
   bind: typeof bind,
+  difference: typeof difference,
 };
 
 
@@ -440,6 +442,7 @@ export const Update = {
   concat,
   Component,
   bind,
+  difference,
 } as UpdateStatic;
 
 export interface BoundStatics<Error, State> {
@@ -460,6 +463,7 @@ export interface BoundStatics<Error, State> {
   modify(proj: (x: State) => State, callback?: () => void): Modify<Error, State, void>;
   effect<Error, Success>(eff: Eff<Error, Success>): Effect<Error, State, Success>;  
   get: Get<Error, State, State>;
+  difference<A>(update: Update<Error, State, A>, diff: (prev: State, next: State) => State|Update<Error, State, void>): Difference<Error, State, A>;
 }
 
 export function bind<Error, State>() {