improve map api types to work with Writable

tim-smart · Sep 22, 2023 · 53d565e · 53d565e
1 parent b012032
commit 53d565e
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diff --git a/.changeset/chilled-ants-dress.md b/.changeset/chilled-ants-dress.md
@@ -0,0 +1,5 @@
+---
+"@effect-rx/rx": patch
+---
+
+improve map api types to work with Writable
diff --git a/docs/rx/Result.ts.md b/docs/rx/Result.ts.md
@@ -34,6 +34,8 @@ Added in v1.0.0
   - [Result (type alias)](#result-type-alias)
   - [Result (namespace)](#result-namespace)
     - [Variance (interface)](#variance-interface)
+    - [Failure (type alias)](#failure-type-alias)
+    - [Success (type alias)](#success-type-alias)
   - [Success (interface)](#success-interface)
   - [Waiting (interface)](#waiting-interface)
 - [refinements](#refinements)
@@ -240,6 +242,26 @@ export interface Variance<E, A> {
 
 Added in v1.0.0
 
+### Failure (type alias)
+
+**Signature**
+
+```ts
+export type Failure<R extends Result<any, any>> = R extends Result<infer E, infer _> ? E : never
+```
+
+Added in v1.0.0
+
+### Success (type alias)
+
+**Signature**
+
+```ts
+export type Success<R extends Result<any, any>> = R extends Result<infer _, infer A> ? A : never
+```
+
+Added in v1.0.0
+
 ## Success (interface)
 
 **Signature**

diff --git a/docs/rx/Rx.ts.md b/docs/rx/Rx.ts.md
@@ -43,6 +43,7 @@ Added in v1.0.0
   - [Rx (namespace)](#rx-namespace)
     - [Get (type alias)](#get-type-alias)
     - [GetResult (type alias)](#getresult-type-alias)
+    - [Infer (type alias)](#infer-type-alias)
     - [Mount (type alias)](#mount-type-alias)
     - [Read (type alias)](#read-type-alias)
     - [ReadFn (type alias)](#readfn-type-alias)
@@ -55,6 +56,8 @@ Added in v1.0.0
   - [RxRuntime (interface)](#rxruntime-interface)
   - [StreamPullResult (type alias)](#streampullresult-type-alias)
   - [Writable (interface)](#writable-interface)
+- [refinements](#refinements)
+  - [isWritable](#iswritable)
 - [type ids](#type-ids)
   - [RefreshableTypeId](#refreshabletypeid)
   - [RefreshableTypeId (type alias)](#refreshabletypeid-type-alias)
@@ -107,7 +110,13 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export declare const map: { <A, B>(f: (_: A) => B): (self: Rx<A>) => Rx<B>; <A, B>(self: Rx<A>, f: (_: A) => B): Rx<B> }
+export declare const map: (<R extends Rx<any>, B>(
+  f: (_: Rx.Infer<R>) => B
+) => (self: R) => [R] extends [Writable<infer _, infer RW>] ? Writable<B, RW> : Rx<B>) &
+  (<R extends Rx<any>, B>(
+    self: R,
+    f: (_: Rx.Infer<R>) => B
+  ) => [R] extends [Writable<infer _, infer RW>] ? Writable<B, RW> : Rx<B>)
 ```
 
 Added in v1.0.0
@@ -117,10 +126,19 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export declare const mapResult: (<A, B>(
-  f: (_: A) => B
-) => <E>(self: Rx<Result.Result<E, A>>) => Rx<Result.Result<E, B>>) &
-  (<E, A, B>(self: Rx<Result.Result<E, A>>, f: (_: A) => B) => Rx<Result.Result<E, B>>)
+export declare const mapResult: (<R extends Rx<Result.Result<any, any>>, B>(
+  f: (_: Result.Result.Success<Rx.Infer<R>>) => B
+) => (
+  self: R
+) => [R] extends [Writable<infer _, infer RW>]
+  ? Writable<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>, RW>
+  : Rx<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>>) &
+  (<R extends Rx<Result.Result<any, any>>, B>(
+    self: R,
+    f: (_: Result.Result.Success<Rx.Infer<R>>) => B
+  ) => [R] extends [Writable<infer _, infer RW>]
+    ? Writable<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>, RW>
+    : Rx<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>>)
 ```
 
 Added in v1.0.0
@@ -420,6 +438,16 @@ export type GetResult = <E, A>(rx: Rx<Result.Result<E, A>>) => Exit.Exit<E | NoS
 
 Added in v1.0.0
 
+### Infer (type alias)
+
+**Signature**
+
+```ts
+export type Infer<T extends Rx<any>> = T extends Rx<infer A> ? A : never
+```
+
+Added in v1.0.0
+
 ### Mount (type alias)
 
 **Signature**
@@ -555,6 +583,18 @@ export interface Writable<R, W> extends Rx<R> {
 
 Added in v1.0.0
 
+# refinements
+
+## isWritable
+
+**Signature**
+
+```ts
+export declare const isWritable: <R, W>(rx: Rx<R>) => rx is Writable<R, W>
+```
+
+Added in v1.0.0
+
 # type ids
 
 ## RefreshableTypeId

diff --git a/packages/rx/src/Result.ts b/packages/rx/src/Result.ts
@@ -46,6 +46,16 @@ export declare namespace Result {
       readonly A: (_: never) => A
     }
   }
+
+  /**
+   * @since 1.0.0
+   */
+  export type Success<R extends Result<any, any>> = R extends Result<infer _, infer A> ? A : never
+
+  /**
+   * @since 1.0.0
+   */
+  export type Failure<R extends Result<any, any>> = R extends Result<infer E, infer _> ? E : never
 }
 
 const ResultProto = Data.struct({

diff --git a/packages/rx/src/Rx.ts b/packages/rx/src/Rx.ts
@@ -107,6 +107,11 @@ export declare namespace Rx {
   export type Subscribe = <A>(rx: Rx<A>, f: (_: A) => void, options?: {
     readonly immediate?: boolean
   }) => () => void
+
+  /**
+   * @since 1.0.0
+   */
+  export type Infer<T extends Rx<any>> = T extends Rx<infer A> ? A : never
 }
 
 /**
@@ -211,6 +216,12 @@ function defaultRefresh(this: Rx<any>, f: any) {
   f(this)
 }
 
+/**
+ * @since 1.0.0
+ * @category refinements
+ */
+export const isWritable = <R, W>(rx: Rx<R>): rx is Writable<R, W> => WritableTypeId in rx
+
 /**
  * @since 1.0.0
  * @category constructors
@@ -744,22 +755,45 @@ export const initialValue: {
  * @since 1.0.0
  * @category combinators
  */
-export const map: {
-  <A, B>(f: (_: A) => B): (self: Rx<A>) => Rx<B>
-  <A, B>(self: Rx<A>, f: (_: A) => B): Rx<B>
-} = dual<
-  <A, B>(f: (_: A) => B) => (self: Rx<A>) => Rx<B>,
-  <A, B>(self: Rx<A>, f: (_: A) => B) => Rx<B>
->(2, (self, f) => readable((get) => f(get(self))))
+export const map = dual<
+  <R extends Rx<any>, B>(
+    f: (_: Rx.Infer<R>) => B
+  ) => (self: R) => [R] extends [Writable<infer _, infer RW>] ? Writable<B, RW> : Rx<B>,
+  <R extends Rx<any>, B>(
+    self: R,
+    f: (_: Rx.Infer<R>) => B
+  ) => [R] extends [Writable<infer _, infer RW>] ? Writable<B, RW> : Rx<B>
+>(
+  2,
+  (<A, B>(self: Rx<A>, f: (_: A) => B): Rx<B> =>
+    isWritable(self)
+      ? writable((get) => f(get(self)), function(ctx, value) {
+        ctx.set(self, value)
+      }, function(refresh) {
+        refresh(self)
+      })
+      : readable((get) => f(get(self)), function(refresh) {
+        refresh(self)
+      })) as any
+)
 
 /**
  * @since 1.0.0
  * @category combinators
  */
 export const mapResult = dual<
-  <A, B>(f: (_: A) => B) => <E>(self: Rx<Result.Result<E, A>>) => Rx<Result.Result<E, B>>,
-  <E, A, B>(self: Rx<Result.Result<E, A>>, f: (_: A) => B) => Rx<Result.Result<E, B>>
->(2, (self, f) => map(self, Result.map(f)))
+  <R extends Rx<Result.Result<any, any>>, B>(
+    f: (_: Result.Result.Success<Rx.Infer<R>>) => B
+  ) => (
+    self: R
+  ) => [R] extends [Writable<infer _, infer RW>] ? Writable<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>, RW>
+    : Rx<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>>,
+  <R extends Rx<Result.Result<any, any>>, B>(
+    self: R,
+    f: (_: Result.Result.Success<Rx.Infer<R>>) => B
+  ) => [R] extends [Writable<infer _, infer RW>] ? Writable<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>, RW>
+    : Rx<Result.Result<Result.Result.Failure<Rx.Infer<R>>, B>>
+>(2, (self, f) => map(self, Result.map(f)) as any)
 
 /**
  * @since 1.0.0