From c0e5befa764c5ac987c7bf109ad56c3896bf5fb0 Mon Sep 17 00:00:00 2001
From: Chris Wilkinson <chris@prereview.org>
Date: Tue, 4 Feb 2025 00:42:34 +0000
Subject: [PATCH] Make it easy to convert a DateTime.Zoned to a DateTime.Utc
 (#4375)

---
 .changeset/sixty-mice-occur.md              |  5 +++++
 packages/effect/src/DateTime.ts             | 17 +++++++++++++++++
 packages/effect/src/internal/dateTime.ts    |  3 +++
 packages/effect/test/DateTime.test.ts       | 17 +++++++++++++++++
 packages/platform-node/test/HttpApi.test.ts |  2 +-
 5 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/sixty-mice-occur.md

diff --git a/.changeset/sixty-mice-occur.md b/.changeset/sixty-mice-occur.md
new file mode 100644
index 00000000000..b339204d760
--- /dev/null
+++ b/.changeset/sixty-mice-occur.md
@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+Make it easy to convert a DateTime.Zoned to a DateTime.Utc
diff --git a/packages/effect/src/DateTime.ts b/packages/effect/src/DateTime.ts
index d50d1bd0241..efe8166d22a 100644
--- a/packages/effect/src/DateTime.ts
+++ b/packages/effect/src/DateTime.ts
@@ -437,6 +437,23 @@ export const unsafeNow: LazyArg<Utc> = Internal.unsafeNow
 // time zones
 // =============================================================================
 
+/**
+ * For a `DateTime` returns a new `DateTime.Utc`.
+ *
+ * @since 3.13.0
+ * @category time zones
+ * @example
+ * ```ts
+ * import { DateTime } from "effect"
+ *
+ * const now = DateTime.unsafeMakeZoned({ year: 2024 }, { timeZone: "Europe/London" })
+ *
+ * // set as UTC
+ * const utc: DateTime.Utc = DateTime.toUtc(now)
+ * ```
+ */
+export const toUtc: (self: DateTime) => Utc = Internal.toUtc
+
 /**
  * Set the time zone of a `DateTime`, returning a new `DateTime.Zoned`.
  *
diff --git a/packages/effect/src/internal/dateTime.ts b/packages/effect/src/internal/dateTime.ts
index 0256bc3b728..e9a0538a8a3 100644
--- a/packages/effect/src/internal/dateTime.ts
+++ b/packages/effect/src/internal/dateTime.ts
@@ -306,6 +306,9 @@ export const unsafeNow: LazyArg<DateTime.Utc> = () => makeUtc(Date.now())
 // time zones
 // =============================================================================
 
+/** @internal */
+export const toUtc = (self: DateTime.DateTime): DateTime.Utc => makeUtc(self.epochMillis)
+
 /** @internal */
 export const setZone: {
   (zone: DateTime.TimeZone, options?: {
diff --git a/packages/effect/test/DateTime.test.ts b/packages/effect/test/DateTime.test.ts
index ca478cff990..04fd7eeb19f 100644
--- a/packages/effect/test/DateTime.test.ts
+++ b/packages/effect/test/DateTime.test.ts
@@ -421,4 +421,21 @@ describe("DateTime", () => {
     const dt = DateTime.unsafeMakeZoned(date)
     deepStrictEqual(dt.zone, DateTime.zoneMakeOffset(60 * 60 * 1000))
   })
+
+  describe("toUtc", () => {
+    it.effect("with a Utc", () =>
+      Effect.gen(function*() {
+        const dt = DateTime.unsafeMake("2024-01-01T01:00:00")
+        strictEqual(dt.toJSON(), "2024-01-01T01:00:00.000Z")
+      }))
+
+    it.effect("with a Zoned", () =>
+      Effect.gen(function*() {
+        const dt = DateTime.unsafeMakeZoned("2024-01-01T01:00:00Z", {
+          timeZone: "Pacific/Auckland",
+          adjustForTimeZone: true
+        })
+        strictEqual(dt.toJSON(), "2023-12-31T12:00:00.000Z")
+      }))
+  })
 })
diff --git a/packages/platform-node/test/HttpApi.test.ts b/packages/platform-node/test/HttpApi.test.ts
index 7d92efced4c..5278ed2eae0 100644
--- a/packages/platform-node/test/HttpApi.test.ts
+++ b/packages/platform-node/test/HttpApi.test.ts
@@ -445,7 +445,7 @@ const HttpUsersLive = HttpApiBuilder.group(
               new User({
                 id: 1,
                 name: `page ${_.headers.page}`,
-                createdAt: DateTime.unsafeMake(now.epochMillis)
+                createdAt: DateTime.toUtc(now)
               })
             ]))
         .handle("upload", (_) =>