Match the JS API for locale arguments (#4806)

thewilkybarkid · web-flow · commit 0b54681cd892 · 2025-05-01T08:48:48.000+12:00
diff --git a/.changeset/proud-humans-wave.md b/.changeset/proud-humans-wave.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Match the JS API for locale arguments
diff --git a/packages/effect/src/DateTime.ts b/packages/effect/src/DateTime.ts
@@ -1445,15 +1445,15 @@ export const format: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime) => string
   (
     self: DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
@@ -1471,15 +1471,15 @@ export const formatLocal: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime) => string
   (
     self: DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
@@ -1497,15 +1497,15 @@ export const formatUtc: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime) => string
   (
     self: DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
diff --git a/packages/effect/src/String.ts b/packages/effect/src/String.ts
@@ -421,7 +421,7 @@ export const lastIndexOf = (searchString: string) => (self: string): Option.Opti
  * @since 2.0.0
  */
 export const localeCompare =
-  (that: string, locales?: Array<string>, options?: Intl.CollatorOptions) => (self: string): Ordering.Ordering =>
+  (that: string, locales?: Intl.LocalesArgument, options?: Intl.CollatorOptions) => (self: string): Ordering.Ordering =>
     number.sign(self.localeCompare(that, locales, options))
 
 /**
@@ -549,7 +549,7 @@ export const search: {
  *
  * @since 2.0.0
  */
-export const toLocaleLowerCase = (locale?: string | Array<string>) => (self: string): string =>
+export const toLocaleLowerCase = (locale?: Intl.LocalesArgument) => (self: string): string =>
   self.toLocaleLowerCase(locale)
 
 /**
@@ -564,7 +564,7 @@ export const toLocaleLowerCase = (locale?: string | Array<string>) => (self: str
  *
  * @since 2.0.0
  */
-export const toLocaleUpperCase = (locale?: string | Array<string>) => (self: string): string =>
+export const toLocaleUpperCase = (locale?: Intl.LocalesArgument) => (self: string): string =>
   self.toLocaleUpperCase(locale)
 
 /**
diff --git a/packages/effect/src/internal/dateTime.ts b/packages/effect/src/internal/dateTime.ts
@@ -1051,23 +1051,23 @@ export const format: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime.DateTime) => string
   (
     self: DateTime.DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
 } = dual(isDateTimeArgs, (
   self: DateTime.DateTime,
   options?:
     | Intl.DateTimeFormatOptions & {
-      readonly locale?: string | undefined
+      readonly locale?: Intl.LocalesArgument
     }
     | undefined
 ): string => {
@@ -1089,23 +1089,23 @@ export const formatLocal: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime.DateTime) => string
   (
     self: DateTime.DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
 } = dual(isDateTimeArgs, (
   self: DateTime.DateTime,
   options?:
     | Intl.DateTimeFormatOptions & {
-      readonly locale?: string | undefined
+      readonly locale?: Intl.LocalesArgument
     }
     | undefined
 ): string => new Intl.DateTimeFormat(options?.locale, options).format(self.epochMillis))
@@ -1115,23 +1115,23 @@ export const formatUtc: {
   (
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): (self: DateTime.DateTime) => string
   (
     self: DateTime.DateTime,
     options?:
       | Intl.DateTimeFormatOptions & {
-        readonly locale?: string | undefined
+        readonly locale?: Intl.LocalesArgument
       }
       | undefined
   ): string
 } = dual(isDateTimeArgs, (
   self: DateTime.DateTime,
   options?:
     | Intl.DateTimeFormatOptions & {
-      readonly locale?: string | undefined
+      readonly locale?: Intl.LocalesArgument
     }
     | undefined
 ): string =>

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"effect": patch
 +---
++
 +Match the JS API for locale arguments
Original file line number	Diff line number	Diff line change
`@@ -1445,15 +1445,15 @@ export const format: {`
`1445`	`1445`	`(`
`1446`	`1446`	`options?:`
`1447`	`1447`	`\| Intl.DateTimeFormatOptions & {`
`1448`		`- readonly locale?: string \| undefined`
	`1448`	`+ readonly locale?: Intl.LocalesArgument`
`1449`	`1449`	`}`
`1450`	`1450`	`\| undefined`
`1451`	`1451`	`): (self: DateTime) => string`
`1452`	`1452`	`(`
`1453`	`1453`	`self: DateTime,`
`1454`	`1454`	`options?:`
`1455`	`1455`	`\| Intl.DateTimeFormatOptions & {`
`1456`		`- readonly locale?: string \| undefined`
	`1456`	`+ readonly locale?: Intl.LocalesArgument`
`1457`	`1457`	`}`
`1458`	`1458`	`\| undefined`
`1459`	`1459`	`): string`
`@@ -1471,15 +1471,15 @@ export const formatLocal: {`
`1471`	`1471`	`(`
`1472`	`1472`	`options?:`
`1473`	`1473`	`\| Intl.DateTimeFormatOptions & {`
`1474`		`- readonly locale?: string \| undefined`
	`1474`	`+ readonly locale?: Intl.LocalesArgument`
`1475`	`1475`	`}`
`1476`	`1476`	`\| undefined`
`1477`	`1477`	`): (self: DateTime) => string`
`1478`	`1478`	`(`
`1479`	`1479`	`self: DateTime,`
`1480`	`1480`	`options?:`
`1481`	`1481`	`\| Intl.DateTimeFormatOptions & {`
`1482`		`- readonly locale?: string \| undefined`
	`1482`	`+ readonly locale?: Intl.LocalesArgument`
`1483`	`1483`	`}`
`1484`	`1484`	`\| undefined`
`1485`	`1485`	`): string`
`@@ -1497,15 +1497,15 @@ export const formatUtc: {`
`1497`	`1497`	`(`
`1498`	`1498`	`options?:`
`1499`	`1499`	`\| Intl.DateTimeFormatOptions & {`
`1500`		`- readonly locale?: string \| undefined`
	`1500`	`+ readonly locale?: Intl.LocalesArgument`
`1501`	`1501`	`}`
`1502`	`1502`	`\| undefined`
`1503`	`1503`	`): (self: DateTime) => string`
`1504`	`1504`	`(`
`1505`	`1505`	`self: DateTime,`
`1506`	`1506`	`options?:`
`1507`	`1507`	`\| Intl.DateTimeFormatOptions & {`
`1508`		`- readonly locale?: string \| undefined`
	`1508`	`+ readonly locale?: Intl.LocalesArgument`
`1509`	`1509`	`}`
`1510`	`1510`	`\| undefined`
`1511`	`1511`	`): string`
Original file line number	Diff line number	Diff line change
`@@ -1051,23 +1051,23 @@ export const format: {`
`1051`	`1051`	`(`
`1052`	`1052`	`options?:`
`1053`	`1053`	`\| Intl.DateTimeFormatOptions & {`
`1054`		`- readonly locale?: string \| undefined`
	`1054`	`+ readonly locale?: Intl.LocalesArgument`
`1055`	`1055`	`}`
`1056`	`1056`	`\| undefined`
`1057`	`1057`	`): (self: DateTime.DateTime) => string`
`1058`	`1058`	`(`
`1059`	`1059`	`self: DateTime.DateTime,`
`1060`	`1060`	`options?:`
`1061`	`1061`	`\| Intl.DateTimeFormatOptions & {`
`1062`		`- readonly locale?: string \| undefined`
	`1062`	`+ readonly locale?: Intl.LocalesArgument`
`1063`	`1063`	`}`
`1064`	`1064`	`\| undefined`
`1065`	`1065`	`): string`
`1066`	`1066`	`} = dual(isDateTimeArgs, (`
`1067`	`1067`	`self: DateTime.DateTime,`
`1068`	`1068`	`options?:`
`1069`	`1069`	`\| Intl.DateTimeFormatOptions & {`
`1070`		`- readonly locale?: string \| undefined`
	`1070`	`+ readonly locale?: Intl.LocalesArgument`
`1071`	`1071`	`}`
`1072`	`1072`	`\| undefined`
`1073`	`1073`	`): string => {`
`@@ -1089,23 +1089,23 @@ export const formatLocal: {`
`1089`	`1089`	`(`
`1090`	`1090`	`options?:`
`1091`	`1091`	`\| Intl.DateTimeFormatOptions & {`
`1092`		`- readonly locale?: string \| undefined`
	`1092`	`+ readonly locale?: Intl.LocalesArgument`
`1093`	`1093`	`}`
`1094`	`1094`	`\| undefined`
`1095`	`1095`	`): (self: DateTime.DateTime) => string`
`1096`	`1096`	`(`
`1097`	`1097`	`self: DateTime.DateTime,`
`1098`	`1098`	`options?:`
`1099`	`1099`	`\| Intl.DateTimeFormatOptions & {`
`1100`		`- readonly locale?: string \| undefined`
	`1100`	`+ readonly locale?: Intl.LocalesArgument`
`1101`	`1101`	`}`
`1102`	`1102`	`\| undefined`
`1103`	`1103`	`): string`
`1104`	`1104`	`} = dual(isDateTimeArgs, (`
`1105`	`1105`	`self: DateTime.DateTime,`
`1106`	`1106`	`options?:`
`1107`	`1107`	`\| Intl.DateTimeFormatOptions & {`
`1108`		`- readonly locale?: string \| undefined`
	`1108`	`+ readonly locale?: Intl.LocalesArgument`
`1109`	`1109`	`}`
`1110`	`1110`	`\| undefined`
`1111`	`1111`	`): string => new Intl.DateTimeFormat(options?.locale, options).format(self.epochMillis))`
`@@ -1115,23 +1115,23 @@ export const formatUtc: {`
`1115`	`1115`	`(`
`1116`	`1116`	`options?:`
`1117`	`1117`	`\| Intl.DateTimeFormatOptions & {`
`1118`		`- readonly locale?: string \| undefined`
	`1118`	`+ readonly locale?: Intl.LocalesArgument`
`1119`	`1119`	`}`
`1120`	`1120`	`\| undefined`
`1121`	`1121`	`): (self: DateTime.DateTime) => string`
`1122`	`1122`	`(`
`1123`	`1123`	`self: DateTime.DateTime,`
`1124`	`1124`	`options?:`
`1125`	`1125`	`\| Intl.DateTimeFormatOptions & {`
`1126`		`- readonly locale?: string \| undefined`
	`1126`	`+ readonly locale?: Intl.LocalesArgument`
`1127`	`1127`	`}`
`1128`	`1128`	`\| undefined`
`1129`	`1129`	`): string`
`1130`	`1130`	`} = dual(isDateTimeArgs, (`
`1131`	`1131`	`self: DateTime.DateTime,`
`1132`	`1132`	`options?:`
`1133`	`1133`	`\| Intl.DateTimeFormatOptions & {`
`1134`		`- readonly locale?: string \| undefined`
	`1134`	`+ readonly locale?: Intl.LocalesArgument`
`1135`	`1135`	`}`
`1136`	`1136`	`\| undefined`
`1137`	`1137`	`): string =>`