Support Refinement in Preficate.tuple and Predicate.struct

.changeset/purple-onions-drive.md

@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+Support `Refinement` in `Predicate.tuple` and `Predicate.struct`

packages/effect/dtslint/Predicate.ts

@@ -271,3 +271,51 @@ pipe(Predicate.isString, Predicate.or(Predicate.isNumber))
 
 // $ExpectType Refinement<unknown, string | number>
 Predicate.or(Predicate.isString, Predicate.isNumber)
+
+// -------------------------------------------------------------------------------------
+// tuple
+// -------------------------------------------------------------------------------------
+
+const isA = hole<Predicate.Refinement<string, "a">>()
+const isTrue = hole<Predicate.Refinement<boolean, true>>()
+const isOdd = hole<Predicate.Predicate<number>>()
+
+// $ExpectType Refinement<readonly [boolean, string], readonly [true, "a"]>
+Predicate.tuple(isTrue, isA)
+
+// $ExpectType Refinement<readonly [boolean, number], readonly [true, number]>
+Predicate.tuple(isTrue, isOdd)
+
+// $ExpectType Predicate<readonly [number, number]>
+Predicate.tuple(isOdd, isOdd)
+
+// $ExpectType Predicate<readonly number[]>
+Predicate.tuple(...hole<Array<Predicate.Predicate<number>>>())
+
+// $ExpectType Refinement<readonly never[], readonly never[]>
+Predicate.tuple(...hole<Array<Predicate.Predicate<number> | Predicate.Refinement<boolean, true>>>())
+
+// $ExpectType Refinement<readonly boolean[], readonly true[]>
+Predicate.tuple(...hole<Array<Predicate.Refinement<boolean, true>>>())
+
+// -------------------------------------------------------------------------------------
+// struct
+// -------------------------------------------------------------------------------------
+
+// $ExpectType Refinement<{ readonly a: string; readonly true: boolean; }, { readonly a: "a"; readonly true: true; }>
+Predicate.struct({
+  a: isA,
+  true: isTrue
+})
+
+// $ExpectType Refinement<{ readonly odd: number; readonly true: boolean; }, { readonly odd: number; readonly true: true; }>
+Predicate.struct({
+  odd: isOdd,
+  true: isTrue
+})
+
+// $ExpectType Predicate<{ readonly odd: number; readonly odd1: number; }>
+Predicate.struct({
+  odd: isOdd,
+  odd1: isOdd
+})

packages/effect/src/Predicate.ts

@@ -29,6 +29,45 @@ export interface Refinement<in A, out B extends A> {
   (a: A): a is B
 }
 
+/**
+ * @since 3.6.0
+ * @category type-level
+ */
+export declare namespace Predicate {
+  /**
+   * @since 3.6.0
+   * @category type-level
+   */
+  export type In<T extends Any> = [T] extends [Predicate<infer _A>] ? _A : never
+  /**
+   * @since 3.6.0
+   * @category type-level
+   */
+  export type Any = Predicate<any>
+}
+
+/**
+ * @since 3.6.0
+ * @category type-level
+ */
+export declare namespace Refinement {
+  /**
+   * @since 3.6.0
+   * @category type-level
+   */
+  export type In<T extends Any> = [T] extends [Refinement<infer _A, infer _>] ? _A : never
+  /**
+   * @since 3.6.0
+   * @category type-level
+   */
+  export type Out<T extends Any> = [T] extends [Refinement<infer _, infer _B>] ? _B : never
+  /**
+   * @since 3.6.0
+   * @category type-level
+   */
+  export type Any = Refinement<any, any>
+}
+
 /**
  * Given a `Predicate<A>` returns a `Predicate<B>`
  *
@@ -686,31 +725,52 @@ export const productMany = <A>(
  * Similar to `Promise.all` but operates on `Predicate`s.
  *
  * ```
+ * [Refinement<A, B>, Refinement<C, D>, ...] -> Refinement<[A, C, ...], [B, D, ...]>
  * [Predicate<A>, Predicate<B>, ...] -> Predicate<[A, B, ...]>
+ * [Refinement<A, B>, Predicate<C>, ...] -> Refinement<[A, C, ...], [B, C, ...]>
  * ```
  *
  * @since 2.0.0
  */
-export const tuple = <T extends ReadonlyArray<Predicate<any>>>(
-  ...elements: T
-): Predicate<Readonly<{ [I in keyof T]: [T[I]] extends [Predicate<infer A>] ? A : never }>> => all(elements) as any
+export const tuple: {
+  <T extends ReadonlyArray<Predicate.Any>>(
+    ...elements: T
+  ): [Extract<T[number], Refinement.Any>] extends [never] ? Predicate<{ readonly [I in keyof T]: Predicate.In<T[I]> }>
+    : Refinement<
+      { readonly [I in keyof T]: T[I] extends Refinement.Any ? Refinement.In<T[I]> : Predicate.In<T[I]> },
+      { readonly [I in keyof T]: T[I] extends Refinement.Any ? Refinement.Out<T[I]> : Predicate.In<T[I]> }
+    >
+} = (...elements: ReadonlyArray<Predicate.Any>) => all(elements) as any
 
 /**
+ * ```
+ * { ab: Refinement<A, B>; cd: Refinement<C, D>, ... } -> Refinement<{ ab: A; cd: C; ... }, { ab: B; cd: D; ... }>
+ * { a: Predicate<A, B>; b: Predicate<B>, ... } -> Predicate<{ a: A; b: B; ... }>
+ * { ab: Refinement<A, B>; c: Predicate<C>, ... } -> Refinement<{ ab: A; c: C; ... }, { ab: B; c: С; ... }>
+ * ```
+ *
  * @since 2.0.0
  */
-export const struct = <R extends Record<string, Predicate<any>>>(
-  fields: R
-): Predicate<{ readonly [K in keyof R]: [R[K]] extends [Predicate<infer A>] ? A : never }> => {
+export const struct: {
+  <R extends Record<string, Predicate.Any>>(
+    fields: R
+  ): [Extract<R[keyof R], Refinement.Any>] extends [never] ?
+    Predicate<{ readonly [K in keyof R]: Predicate.In<R[K]> }> :
+    Refinement<
+      { readonly [K in keyof R]: R[K] extends Refinement.Any ? Refinement.In<R[K]> : Predicate.In<R[K]> },
+      { readonly [K in keyof R]: R[K] extends Refinement.Any ? Refinement.Out<R[K]> : Predicate.In<R[K]> }
+    >
+} = (<R extends Record<string, Predicate.Any>>(fields: R) => {
   const keys = Object.keys(fields)
-  return (a) => {
+  return (a: Record<string, unknown>) => {
     for (const key of keys) {
       if (!fields[key](a[key])) {
         return false
       }
     }
     return true
   }
-}
+}) as any
 
 /**
  * Negates the result of a given predicate.