From 8890c1d08dac7b585fb16faf07e39ee21e7f230f Mon Sep 17 00:00:00 2001
From: Jake Jarvis <jake@jarv.is>
Date: Fri, 21 Mar 2025 13:20:42 -0400
Subject: [PATCH] =?UTF-8?q?dayjs=20=E2=9E=A1=EF=B8=8F=20=20date-fns?=
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---
 app/notes/[slug]/page.tsx                |  2 +-
 app/notes/page.tsx                       |  2 +-
 app/projects/page.tsx                    |  3 +--
 components/RelativeTime/RelativeTime.tsx | 23 ++++++++++------
 components/Time/Time.tsx                 | 18 +++++++++----
 lib/helpers/format-date.ts               | 34 ------------------------
 lib/helpers/posts.ts                     |  3 +--
 package.json                             |  4 ++-
 pnpm-lock.yaml                           | 28 ++++++++++++++-----
 9 files changed, 57 insertions(+), 60 deletions(-)
 delete mode 100644 lib/helpers/format-date.ts

diff --git a/app/notes/[slug]/page.tsx b/app/notes/[slug]/page.tsx
index cbe2ae32..de606f9d 100644
--- a/app/notes/[slug]/page.tsx
+++ b/app/notes/[slug]/page.tsx
@@ -87,7 +87,7 @@ const Page = async ({ params }: { params: Promise<{ slug: string }> }) => {
         <div className={styles.metaItem}>
           <Link href={`/notes/${frontmatter.slug}` as Route} plain className={styles.metaLink}>
             <CalendarIcon size="1.2em" className={styles.metaIcon} />
-            <Time date={frontmatter.date} format="MMMM D, YYYY" />
+            <Time date={frontmatter.date} format="MMMM d, y" />
           </Link>
         </div>
 
diff --git a/app/notes/page.tsx b/app/notes/page.tsx
index 0fc2fff5..5aefcdbb 100644
--- a/app/notes/page.tsx
+++ b/app/notes/page.tsx
@@ -38,7 +38,7 @@ const Page = async () => {
         <ul className={styles.list}>
           {posts.map(({ slug, date, title, htmlTitle }) => (
             <li className={styles.post} key={slug}>
-              <Time date={date} format="MMM D" className={styles.postDate} />
+              <Time date={date} format="MMM d" className={styles.postDate} />
               <span>
                 <Link href={`/notes/${slug}` as Route} dangerouslySetInnerHTML={{ __html: htmlTitle || title }} />
               </span>
diff --git a/app/projects/page.tsx b/app/projects/page.tsx
index b0521095..749b52c5 100644
--- a/app/projects/page.tsx
+++ b/app/projects/page.tsx
@@ -152,9 +152,8 @@ const Page = async () => {
                 </div>
               )}
 
-              {/* only use relative "time ago" on client side, since it'll be outdated via SSG and cause hydration errors */}
               <div className={styles.metaItem}>
-                <RelativeTime date={repo.updatedAt} verb="Updated" staticFormat="MMM D, YYYY" />
+                Updated <RelativeTime date={repo.updatedAt} />
               </div>
             </div>
           </div>
diff --git a/components/RelativeTime/RelativeTime.tsx b/components/RelativeTime/RelativeTime.tsx
index 1783f58b..f8d6bdb9 100644
--- a/components/RelativeTime/RelativeTime.tsx
+++ b/components/RelativeTime/RelativeTime.tsx
@@ -1,24 +1,31 @@
 "use client";
 
 import { useHasMounted } from "../../hooks";
-import { formatDate, formatTimeAgo } from "../../lib/helpers/format-date";
+import { format, formatISO, formatDistanceToNowStrict } from "date-fns";
+import { enUS } from "date-fns/locale";
+import { tz } from "@date-fns/tz";
+import { utc } from "@date-fns/utc";
+import * as config from "../../lib/config";
 import type { ComponentPropsWithoutRef } from "react";
 
 export type RelativeTimeProps = ComponentPropsWithoutRef<"time"> & {
-  date: string | number | Date;
-  verb?: string; // optional "Updated", "Published", "Created", etc.
-  staticFormat?: string; // format for the placeholder/fallback before client-side renders the relative time
+  date: string;
 };
 
-const RelativeTime = ({ date, verb, staticFormat, ...rest }: RelativeTimeProps) => {
+const RelativeTime = ({ date, ...rest }: RelativeTimeProps) => {
   // play nice with SSR -- only use relative time on the client, since it'll quickly become outdated on the server and
   // cause a react hydration mismatch error.
   const hasMounted = useHasMounted();
 
   return (
-    <time dateTime={formatDate(date)} title={formatDate(date, "MMM D, YYYY, h:mm A z")} {...rest}>
-      {verb && `${verb} `}
-      {hasMounted ? formatTimeAgo(date, { suffix: true }) : `on ${formatDate(date, staticFormat)}`}
+    <time
+      dateTime={formatISO(date, { in: utc })}
+      title={format(date, "MMM d, y, h:mm a O", { in: tz(config.timeZone), locale: enUS })}
+      {...rest}
+    >
+      {hasMounted
+        ? formatDistanceToNowStrict(date, { locale: enUS, addSuffix: true })
+        : `on ${format(date, "MMM d, y", { in: tz(config.timeZone), locale: enUS })}`}
     </time>
   );
 };
diff --git a/components/Time/Time.tsx b/components/Time/Time.tsx
index c549b0fd..7323acdf 100644
--- a/components/Time/Time.tsx
+++ b/components/Time/Time.tsx
@@ -1,15 +1,23 @@
-import { formatDate } from "../../lib/helpers/format-date";
+import { format, formatISO } from "date-fns";
+import { enUS } from "date-fns/locale";
+import { tz } from "@date-fns/tz";
+import { utc } from "@date-fns/utc";
+import * as config from "../../lib/config";
 import type { ComponentPropsWithoutRef } from "react";
 
 export type TimeProps = ComponentPropsWithoutRef<"time"> & {
-  date: string | number | Date;
+  date: string;
   format?: string;
 };
 
-const Time = ({ date, format = "MMM D", ...rest }: TimeProps) => {
+const Time = ({ date, format: formatStr = "PPpp", ...rest }: TimeProps) => {
   return (
-    <time dateTime={formatDate(date)} title={formatDate(date, "MMM D, YYYY, h:mm A z")} {...rest}>
-      {formatDate(date, format)}
+    <time
+      dateTime={formatISO(date, { in: utc })}
+      title={format(date, "MMM d, y, h:mm a O", { in: tz(config.timeZone), locale: enUS })}
+      {...rest}
+    >
+      {format(date, formatStr, { in: tz(config.timeZone), locale: enUS })}
     </time>
   );
 };
diff --git a/lib/helpers/format-date.ts b/lib/helpers/format-date.ts
deleted file mode 100644
index 2e4f921c..00000000
--- a/lib/helpers/format-date.ts
+++ /dev/null
@@ -1,34 +0,0 @@
-import dayjs from "dayjs";
-import dayjsUtc from "dayjs/plugin/utc";
-import dayjsTimezone from "dayjs/plugin/timezone";
-import dayjsRelativeTime from "dayjs/plugin/relativeTime";
-import dayjsLocalizedFormat from "dayjs/plugin/localizedFormat";
-import dayjsAdvancedFormat from "dayjs/plugin/advancedFormat";
-import "dayjs/locale/en";
-import * as config from "../config";
-
-const IsomorphicDayJs = (date?: dayjs.ConfigType): dayjs.Dayjs => {
-  // plugins
-  dayjs.extend(dayjsUtc);
-  dayjs.extend(dayjsTimezone);
-  dayjs.extend(dayjsRelativeTime);
-  dayjs.extend(dayjsLocalizedFormat);
-  dayjs.extend(dayjsAdvancedFormat);
-
-  return dayjs(date).locale("en").tz(config.timeZone).clone();
-};
-
-// simple wrapper around dayjs.format() to normalize timezone across the site, both server and client side, to prevent
-// hydration errors by returning an instance of dayjs with these defaults set.
-// date defaults to now, format defaults to ISO 8601 (e.g. 2022-04-07T21:53:33-04:00)
-export const formatDate = (date?: dayjs.ConfigType, formatStr?: string): string => {
-  return IsomorphicDayJs(date).format(formatStr);
-};
-
-// returns the human-friendly difference between now and given date (e.g. "5 minutes", "9 months", etc.)
-// set `{ suffix: true }` to include the "... ago" or "in ..." for past/future
-export const formatTimeAgo = (date: dayjs.ConfigType, options?: { suffix?: boolean }): string => {
-  return IsomorphicDayJs().isBefore(date)
-    ? IsomorphicDayJs(date).toNow(!options?.suffix)
-    : IsomorphicDayJs(date).fromNow(!options?.suffix);
-};
diff --git a/lib/helpers/posts.ts b/lib/helpers/posts.ts
index 77327a68..e937e117 100644
--- a/lib/helpers/posts.ts
+++ b/lib/helpers/posts.ts
@@ -4,7 +4,6 @@ import glob from "fast-glob";
 import { unified } from "unified";
 import { remarkHtml, remarkParse, remarkSmartypants } from "./remark-rehype-plugins";
 import { decode } from "html-entities";
-import { formatDate } from "./format-date";
 import { BASE_URL, POSTS_DIR } from "../config/constants";
 
 export type FrontMatter = {
@@ -48,7 +47,7 @@ export const getFrontMatter = async (slug: string): Promise<FrontMatter> => {
     // stylized title with limited html tags:
     htmlTitle,
     slug,
-    date: formatDate(frontmatter.date), // validate/normalize the date string provided from front matter
+    date: new Date(frontmatter.date).toISOString(), // validate/normalize the date string provided from front matter
     permalink: `${BASE_URL}/${POSTS_DIR}/${slug}`,
   };
 };
diff --git a/package.json b/package.json
index 2652820a..972bc995 100644
--- a/package.json
+++ b/package.json
@@ -18,6 +18,8 @@
     "postinstall": "prisma generate --no-hints"
   },
   "dependencies": {
+    "@date-fns/tz": "^1.2.0",
+    "@date-fns/utc": "^2.1.0",
     "@emotion/hash": "^0.9.2",
     "@giscus/react": "^3.1.0",
     "@mdx-js/loader": "^3.1.0",
@@ -31,7 +33,7 @@
     "clsx": "^2.1.1",
     "comma-number": "^2.1.0",
     "copy-to-clipboard": "^3.3.3",
-    "dayjs": "^1.11.13",
+    "date-fns": "^4.1.0",
     "fast-glob": "^3.3.3",
     "feed": "^4.2.2",
     "geist": "^1.3.1",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f6d4b2d5..140b856a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -8,6 +8,12 @@ importers:
 
   .:
     dependencies:
+      '@date-fns/tz':
+        specifier: ^1.2.0
+        version: 1.2.0
+      '@date-fns/utc':
+        specifier: ^2.1.0
+        version: 2.1.0
       '@emotion/hash':
         specifier: ^0.9.2
         version: 0.9.2
@@ -47,9 +53,9 @@ importers:
       copy-to-clipboard:
         specifier: ^3.3.3
         version: 3.3.3
-      dayjs:
-        specifier: ^1.11.13
-        version: 1.11.13
+      date-fns:
+        specifier: ^4.1.0
+        version: 4.1.0
       fast-glob:
         specifier: ^3.3.3
         version: 3.3.3
@@ -389,6 +395,12 @@ packages:
     peerDependencies:
       postcss-selector-parser: ^7.0.0
 
+  '@date-fns/tz@1.2.0':
+    resolution: {integrity: sha512-LBrd7MiJZ9McsOgxqWX7AaxrDjcFVjWH/tIKJd7pnR7McaslGYOP1QmmiBXdJH/H/yLCT+rcQ7FaPBUxRGUtrg==}
+
+  '@date-fns/utc@2.1.0':
+    resolution: {integrity: sha512-176grgAgU2U303rD2/vcOmNg0kGPbhzckuH1TEP2al7n0AQipZIy9P15usd2TKQCG1g+E1jX/ZVQSzs4sUDwgA==}
+
   '@discoveryjs/json-ext@0.5.7':
     resolution: {integrity: sha512-dBVuXR082gk3jsFp7Rd/JI4kytwGHecnCoTtXFb7DB6CNHp4rg5k1bhg0nWdLGLnOV71lmDzGQaLMy8iPLY0pw==}
     engines: {node: '>=10.0.0'}
@@ -1515,8 +1527,8 @@ packages:
     resolution: {integrity: sha512-BS8PfmtDGnrgYdOonGZQdLZslWIeCGFP9tpan0hi1Co2Zr2NKADsvGYA8XxuG/4UWgJ6Cjtv+YJnB6MM69QGlQ==}
     engines: {node: '>= 0.4'}
 
-  dayjs@1.11.13:
-    resolution: {integrity: sha512-oaMBel6gjolK862uaPQOVTA7q3TZhuSvuMQAAglQDOWYO9A91IrAOUJEyKVlqJlHE0vq5p5UXxzdPfMH/x6xNg==}
+  date-fns@4.1.0:
+    resolution: {integrity: sha512-Ukq0owbQXxa/U3EGtsdVBkR1w7KOQ5gIBqdH2hkvknzZPYvBxb/aa6E8L7tmjFtkwZBu3UXBbjIgPo/Ez4xaNg==}
 
   debounce@1.2.1:
     resolution: {integrity: sha512-XRRe6Glud4rd/ZGQfiV1ruXSfbvfJedlV9Y6zOlP+2K04vBYiJEte6stfFkCP03aMnY5tsipamumUjL14fofug==}
@@ -4067,6 +4079,10 @@ snapshots:
     dependencies:
       postcss-selector-parser: 7.1.0
 
+  '@date-fns/tz@1.2.0': {}
+
+  '@date-fns/utc@2.1.0': {}
+
   '@discoveryjs/json-ext@0.5.7': {}
 
   '@dual-bundle/import-meta-resolve@4.1.0': {}
@@ -5162,7 +5178,7 @@ snapshots:
       es-errors: 1.3.0
       is-data-view: 1.0.2
 
-  dayjs@1.11.13: {}
+  date-fns@4.1.0: {}
 
   debounce@1.2.1: {}