Improve DateTime type preservation (#4255)

Co-authored-by: Tim <[email protected]>

.changeset/fuzzy-roses-rush.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Improve DateTime type preservation

packages/effect/dtslint/DateTime.ts

@@ -0,0 +1,91 @@
+import * as DateTime from "effect/DateTime"
+
+declare const utc: DateTime.Utc
+declare const zoned: DateTime.Zoned
+declare const any: DateTime.DateTime
+
+// -------------------------------------------------------------------------------------
+// min
+// -------------------------------------------------------------------------------------
+
+// $ExpectType Utc | Zoned
+DateTime.min(utc, zoned)
+
+// $ExpectType Utc
+DateTime.min(utc, utc)
+
+// $ExpectType Zoned
+DateTime.min(zoned, zoned)
+
+// $ExpectType DateTime
+DateTime.min(any, zoned)
+
+// $ExpectType DateTime
+DateTime.min(any, utc)
+
+// $ExpectType DateTime
+DateTime.min(any, any)
+
+// $ExpectType Utc | Zoned
+utc.pipe(DateTime.min(zoned))
+
+// $ExpectType Utc | Zoned
+zoned.pipe(DateTime.min(utc))
+
+// $ExpectType Utc
+utc.pipe(DateTime.min(utc))
+
+// $ExpectType Zoned
+zoned.pipe(DateTime.min(zoned))
+
+// $ExpectType DateTime
+any.pipe(DateTime.min(zoned))
+
+// $ExpectType DateTime
+any.pipe(DateTime.min(utc))
+
+// $ExpectType DateTime
+any.pipe(DateTime.min(any))
+
+// -------------------------------------------------------------------------------------
+// max
+// -------------------------------------------------------------------------------------
+
+// $ExpectType Utc | Zoned
+DateTime.max(utc, zoned)
+
+// $ExpectType Utc
+DateTime.max(utc, utc)
+
+// $ExpectType Zoned
+DateTime.max(zoned, zoned)
+
+// $ExpectType DateTime
+DateTime.max(any, zoned)
+
+// $ExpectType DateTime
+DateTime.max(any, utc)
+
+// $ExpectType DateTime
+DateTime.max(any, any)
+
+// $ExpectType Utc | Zoned
+utc.pipe(DateTime.max(zoned))
+
+// $ExpectType Utc | Zoned
+zoned.pipe(DateTime.max(utc))
+
+// $ExpectType Utc
+utc.pipe(DateTime.max(utc))
+
+// $ExpectType Zoned
+zoned.pipe(DateTime.max(zoned))
+
+// $ExpectType DateTime
+any.pipe(DateTime.max(zoned))
+
+// $ExpectType DateTime
+any.pipe(DateTime.max(utc))
+
+// $ExpectType DateTime
+any.pipe(DateTime.max(any))

packages/effect/src/DateTime.ts

@@ -279,8 +279,13 @@ export const Order: order.Order<DateTime> = Internal.Order
  * @since 3.6.0
  */
 export const clamp: {
-  (options: { minimum: DateTime; maximum: DateTime }): (self: DateTime) => DateTime
-  (self: DateTime, options: { minimum: DateTime; maximum: DateTime }): DateTime
+  <Min extends DateTime, Max extends DateTime>(
+    options: { readonly minimum: Min; readonly maximum: Max }
+  ): <A extends DateTime>(self: A) => A | Min | Max
+  <A extends DateTime, Min extends DateTime, Max extends DateTime>(
+    self: A,
+    options: { readonly minimum: Min; readonly maximum: Max }
+  ): A | Min | Max
 } = Internal.clamp
 
 // =============================================================================
@@ -704,17 +709,17 @@ export const distanceDuration: {
  * @category comparisons
  */
 export const min: {
-  (that: DateTime): (self: DateTime) => DateTime
-  (self: DateTime, that: DateTime): DateTime
+  <That extends DateTime>(that: That): <Self extends DateTime>(self: Self) => Self | That
+  <Self extends DateTime, That extends DateTime>(self: Self, that: That): Self | That
 } = Internal.min
 
 /**
  * @since 3.6.0
  * @category comparisons
  */
 export const max: {
-  (that: DateTime): (self: DateTime) => DateTime
-  (self: DateTime, that: DateTime): DateTime
+  <That extends DateTime>(that: That): <Self extends DateTime>(self: Self) => Self | That
+  <Self extends DateTime, That extends DateTime>(self: Self, that: That): Self | That
 } = Internal.max
 
 /**
@@ -929,13 +934,8 @@ export const getPart: {
  * @category parts
  */
 export const setParts: {
-  (
-    parts: Partial<DateTime.PartsWithWeekday>
-  ): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(
-    self: A,
-    parts: Partial<DateTime.PartsWithWeekday>
-  ): DateTime.PreserveZone<A>
+  (parts: Partial<DateTime.PartsWithWeekday>): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, parts: Partial<DateTime.PartsWithWeekday>): A
 } = Internal.setParts
 
 /**
@@ -945,13 +945,8 @@ export const setParts: {
  * @category parts
  */
 export const setPartsUtc: {
-  (
-    parts: Partial<DateTime.PartsWithWeekday>
-  ): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(
-    self: A,
-    parts: Partial<DateTime.PartsWithWeekday>
-  ): DateTime.PreserveZone<A>
+  (parts: Partial<DateTime.PartsWithWeekday>): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, parts: Partial<DateTime.PartsWithWeekday>): A
 } = Internal.setPartsUtc
 
 // =============================================================================
@@ -1127,8 +1122,8 @@ export const nowInCurrentZone: Effect.Effect<Zoned, never, CurrentTimeZone> = Ef
  * @category mapping
  */
 export const mutate: {
-  (f: (date: Date) => void): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, f: (date: Date) => void): DateTime.PreserveZone<A>
+  (f: (date: Date) => void): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, f: (date: Date) => void): A
 } = Internal.mutate
 
 /**
@@ -1138,8 +1133,8 @@ export const mutate: {
  * @category mapping
  */
 export const mutateUtc: {
-  (f: (date: Date) => void): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, f: (date: Date) => void): DateTime.PreserveZone<A>
+  (f: (date: Date) => void): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, f: (date: Date) => void): A
 } = Internal.mutateUtc
 
 /**
@@ -1159,8 +1154,8 @@ export const mutateUtc: {
  * ```
  */
 export const mapEpochMillis: {
-  (f: (millis: number) => number): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, f: (millis: number) => number): DateTime.PreserveZone<A>
+  (f: (millis: number) => number): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, f: (millis: number) => number): A
 } = Internal.mapEpochMillis
 
 /**
@@ -1240,8 +1235,8 @@ export const match: {
  * ```
  */
 export const addDuration: {
-  (duration: Duration.DurationInput): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, duration: Duration.DurationInput): DateTime.PreserveZone<A>
+  (duration: Duration.DurationInput): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, duration: Duration.DurationInput): A
 } = Internal.addDuration
 
 /**
@@ -1260,8 +1255,8 @@ export const addDuration: {
  * ```
  */
 export const subtractDuration: {
-  (duration: Duration.DurationInput): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, duration: Duration.DurationInput): DateTime.PreserveZone<A>
+  (duration: Duration.DurationInput): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, duration: Duration.DurationInput): A
 } = Internal.subtractDuration
 
 /**
@@ -1283,13 +1278,8 @@ export const subtractDuration: {
  * ```
  */
 export const add: {
-  (
-    parts: Partial<DateTime.PartsForMath>
-  ): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(
-    self: A,
-    parts: Partial<DateTime.PartsForMath>
-  ): DateTime.PreserveZone<A>
+  (parts: Partial<DateTime.PartsForMath>): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, parts: Partial<DateTime.PartsForMath>): A
 } = Internal.add
 
 /**
@@ -1308,13 +1298,8 @@ export const add: {
  * ```
  */
 export const subtract: {
-  (
-    parts: Partial<DateTime.PartsForMath>
-  ): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(
-    self: A,
-    parts: Partial<DateTime.PartsForMath>
-  ): DateTime.PreserveZone<A>
+  (parts: Partial<DateTime.PartsForMath>): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(self: A, parts: Partial<DateTime.PartsForMath>): A
 } = Internal.subtract
 
 /**
@@ -1337,12 +1322,15 @@ export const subtract: {
  * ```
  */
 export const startOf: {
-  (part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): DateTime.PreserveZone<A>
+  (
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(
+    self: A,
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): A
 } = Internal.startOf
 
 /**
@@ -1365,12 +1353,15 @@ export const startOf: {
  * ```
  */
 export const endOf: {
-  (part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): DateTime.PreserveZone<A>
+  (
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(
+    self: A,
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): A
 } = Internal.endOf
 
 /**
@@ -1393,12 +1384,15 @@ export const endOf: {
  * ```
  */
 export const nearest: {
-  (part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): <A extends DateTime>(self: A) => DateTime.PreserveZone<A>
-  <A extends DateTime>(self: A, part: DateTime.UnitSingular, options?: {
-    readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined
-  }): DateTime.PreserveZone<A>
+  (
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): <A extends DateTime>(self: A) => A
+  <A extends DateTime>(
+    self: A,
+    part: DateTime.UnitSingular,
+    options?: { readonly weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined }
+  ): A
 } = Internal.nearest
 
 // =============================================================================