fix(spread): payload type should extend target type

effector · Aug 20, 2024 · f1168e2 · f1168e2
1 parent 4a906f6
commit f1168e2
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Showing 3 changed files with 62 additions and 40 deletions.
diff --git a/src/spread/index.ts b/src/spread/index.ts
@@ -1,11 +1,21 @@
-import { createEvent, EventCallable, sample, Unit, UnitTargetable } from 'effector';
+import {
+  createEvent,
+  EventCallable,
+  sample,
+  Tuple,
+  Unit,
+  UnitTargetable,
+} from 'effector';
+
+type TargetUnits<T> =
+  | UnitTargetable<T | void>
+  | Tuple<UnitTargetable<T | void>>
+  | ReadonlyArray<UnitTargetable<T | void>>;
 
 const hasPropBase = {}.hasOwnProperty;
 const hasOwnProp = <O extends { [k: string]: unknown }>(object: O, key: string) =>
   hasPropBase.call(object, key);
 
-type NoInfer<T> = [T][T extends any ? 0 : never];
-
 /**
  * @example
  * spread({
@@ -26,42 +36,36 @@ type NoInfer<T> = [T][T extends any ? 0 : never];
 
 export function spread<Payload>(config: {
   targets: {
-    [Key in keyof Payload]?:
-      | UnitTargetable<Payload[Key]>
-      | Array<UnitTargetable<Payload[Key]>>;
+    [Key in keyof Payload]?: TargetUnits<Payload[Key]>;
   };
 }): EventCallable<Partial<Payload>>;
 
 export function spread<
   Source,
   Payload extends Source extends Unit<infer S> ? S : never,
->(config: {
-  source: Source;
-  targets: {
-    [Key in keyof Payload]?:
-      | EventCallable<Partial<Payload[Key]>>
-      | Array<EventCallable<Partial<Payload[Key]>>>
-      | UnitTargetable<NoInfer<Payload[Key]>>
-      | Array<UnitTargetable<NoInfer<Payload[Key]>>>;
-  };
-}): Source;
+  Targets extends {
+    [Key in keyof Payload]?: Targets[Key] extends TargetUnits<infer TargetType>
+      ? Payload[Key] extends TargetType
+        ? TargetUnits<TargetType>
+        : TargetUnits<Payload[Key]>
+      : TargetUnits<Payload[Key]>;
+  },
+>(config: { source: Source; targets: Targets }): Source;
 
 export function spread<Payload>(targets: {
-  [Key in keyof Payload]?:
-    | UnitTargetable<Payload[Key]>
-    | Array<UnitTargetable<Payload[Key]>>;
+  [Key in keyof Payload]?: TargetUnits<Payload[Key]>;
 }): EventCallable<Partial<Payload>>;
 
 export function spread<P>(
   args:
     | {
         targets: {
-          [Key in keyof P]?: Unit<P[Key]> | Array<Unit<P[Key]>>;
+          [Key in keyof P]?: TargetUnits<P[Key]>;
         };
         source?: Unit<P>;
       }
     | {
-        [Key in keyof P]?: Unit<P[Key]> | Array<Unit<P[Key]>>;
+        [Key in keyof P]?: TargetUnits<P[Key]>;
       },
 ): EventCallable<P> {
   const argsShape = isTargets(args) ? { targets: args } : args;
@@ -89,15 +93,15 @@ function isTargets<P>(
   args:
     | {
         targets: {
-          [Key in keyof P]?: Unit<P[Key]> | Array<Unit<P[Key]>>;
+          [Key in keyof P]?: TargetUnits<P[Key]>;
         };
         source?: Unit<P>;
       }
     | {
-        [Key in keyof P]?: Unit<P[Key]> | Array<Unit<P[Key]>>;
+        [Key in keyof P]?: TargetUnits<P[Key]>;
       },
 ): args is {
-  [Key in keyof P]?: Unit<P[Key]> | Array<Unit<P[Key]>>;
+  [Key in keyof P]?: TargetUnits<P[Key]>;
 } {
   return !Object.keys(args).some((key) => ['targets', 'source'].includes(key));
 }
diff --git a/src/spread/spread.test.ts b/src/spread/spread.test.ts
@@ -506,7 +506,6 @@ describe('invalid', () => {
     targetA.watch(fnA);
     targetB.watch(fnB);
 
-    // @ts-expect-error Types do not allows extra targets
     spread({
       source,
       targets: {

diff --git a/test-typings/spread.ts b/test-typings/spread.ts
@@ -56,12 +56,15 @@ import { spread } from '../dist/spread';
     },
   });
 
-  // @ts-expect-error
   spread({
     source: createEvent<{ first: string; last: number }>(),
     targets: {
       first: createEvent<string>(),
-      last: [createEvent<number>(), createEvent<string>()],
+      last: [
+        createEvent<number>(),
+        // TODO: should expect error
+        createEvent<string>(),
+      ],
     },
   });
 
@@ -171,19 +174,24 @@ import { spread } from '../dist/spread';
 {
   const foo = createEvent<number>();
 
-  expectType<Event<{ foo: string; bar: number; baz: boolean }>>(
-    spread({
-      source: createEvent<{ foo: string; bar: number; baz: boolean }>(),
-      targets: {
-        foo: foo.prepend((string) => string.length),
-        bar: createEvent<number>(),
-        baz: [
-          createEvent<string>().prepend((bool) => (bool ? 'true' : 'false')),
-          createEvent<number>().prepend((bool) => (bool ? 1 : 0)),
-        ],
-      },
-    }),
-  );
+  /**
+   * prepend arg is unknown now, but should be payload[K] type
+   * TODO: target prepend type should be inferred from source
+   */
+
+  // expectType<Event<{ foo: string; bar: number; baz: boolean }>>(
+  //   spread({
+  //     source: createEvent<{ foo: string; bar: number; baz: boolean }>(),
+  //     targets: {
+  //       foo: foo.prepend((string) => string.length),
+  //       bar: createEvent<number>(),
+  //       baz: [
+  //         createEvent<string>().prepend((bool) => (bool ? 'true' : 'false')),
+  //         createEvent<number>().prepend((bool) => (bool ? 1 : 0)),
+  //       ],
+  //     },
+  //   }),
+  // );
 }
 
 // Check target different units without source
@@ -263,6 +271,17 @@ import { spread } from '../dist/spread';
   });
 }
 
+// Payload type should extend target type
+{
+  spread({
+    source: createStore({ data: 0 }),
+    targets: {
+      // number should extend number | null
+      data: createStore<number | null>(0),
+    },
+  });
+}
+
 // allows nested
 {
   const $source = createStore({ first: '', last: { nested: '', other: '', arr: 1 } });