feat(util): add timeZone option

Author: yoshinorin

__tests__/unit/utils/time.test.ts

@@ -15,3 +15,17 @@ test("splittedBy", () => {
   expect(result[1]).toEqual("02");
   // .toEqual(['2022', '02', '06'])  NOTE: local -> JST, CI -> UTC
 });
+
+test("splittedBy: with timezone", () => {
+  // 2022-02-05T15:33:26Z is 2022-02-06 00:33 in JST
+  expect(splittedBy(1644075206, "ja-JP", "/", "Asia/Tokyo")).toEqual([
+    "2022",
+    "02",
+    "06"
+  ]);
+  expect(splittedBy(1644075206, "ja-JP", "/", "UTC")).toEqual([
+    "2022",
+    "02",
+    "05"
+  ]);
+});

src/utils/time.ts

@@ -25,13 +25,15 @@ export function toISODateString(unixTime: number): string {
 export function splittedBy(
   unixTime: number,
   locale: string,
-  delimiter: string
+  delimiter: string,
+  timeZone?: string
 ): Array<string> {
   return toDate(unixTime)
     .toLocaleDateString(locale, {
       year: "numeric",
       month: "2-digit",
-      day: "2-digit"
+      day: "2-digit",
+      ...(timeZone ? { timeZone } : {})
     })
     .split(delimiter);
 }