From 93de138ff3e0449f1935a5c40d65380ae7473de7 Mon Sep 17 00:00:00 2001
From: Bao Trinh <qubidt@gmail.com>
Date: Thu, 5 Dec 2024 03:49:08 -0600
Subject: [PATCH] feat(dates): allow configurable default timezone

---
 docs/configuration.md | 1 +
 quartz/build.ts       | 1 +
 quartz/cfg.ts         | 6 ++++++
 3 files changed, 8 insertions(+)

diff --git a/docs/configuration.md b/docs/configuration.md
index 1622da6fa414a..dfa0b5bb57651 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -35,6 +35,7 @@ This part of the configuration concerns anything that can affect the whole site.
   - `{ provider: 'cabin' }` or `{ provider: 'cabin', host: 'https://cabin.example.com' }` (custom domain): use [Cabin](https://withcabin.com);
   - `{provider: 'clarity', projectId: '<your-clarity-id-code' }`: use [Microsoft clarity](https://clarity.microsoft.com/). The project id can be found on top of the overview page.
 - `locale`: used for [[i18n]] and date formatting
+- `timezone`: timezone for interpreting dates (IANA format), when not specified in the datetime string; defaults to the system's local zone.
 - `baseUrl`: this is used for sitemaps and RSS feeds that require an absolute URL to know where the canonical 'home' of your site lives. This is normally the deployed URL of your site (e.g. `quartz.jzhao.xyz` for this site). Do not include the protocol (i.e. `https://`) or any leading or trailing slashes.
   - This should also include the subpath if you are [[hosting]] on GitHub pages without a custom domain. For example, if my repository is `jackyzha0/quartz`, GitHub pages would deploy to `https://jackyzha0.github.io/quartz` and the `baseUrl` would be `jackyzha0.github.io/quartz`.
   - Note that Quartz 4 will avoid using this as much as possible and use relative URLs whenever it can to make sure your site works no matter _where_ you end up actually deploying it.
diff --git a/quartz/build.ts b/quartz/build.ts
index f783904b81666..ed316fa06bfcc 100644
--- a/quartz/build.ts
+++ b/quartz/build.ts
@@ -56,6 +56,7 @@ async function buildQuartz(argv: Argv, mut: Mutex, clientRefresh: () => void) {
 
   LuxonSettings.throwOnInvalid = true
   LuxonSettings.defaultLocale = cfg.configuration.locale
+  if (cfg.configuration.timezone) LuxonSettings.defaultZone = cfg.configuration.timezone
 
   const pluginCount = Object.values(cfg.plugins).flat().length
   const pluginNames = (key: "transformers" | "filters" | "emitters") =>
diff --git a/quartz/cfg.ts b/quartz/cfg.ts
index 135f584994a6d..3aaa4999e378c 100644
--- a/quartz/cfg.ts
+++ b/quartz/cfg.ts
@@ -75,6 +75,12 @@ export interface GlobalConfiguration {
    * Region Codes: https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
    */
   locale: ValidLocale
+  /**
+   * The default timezone when handling dates.
+   * Valid options are "system" (default), "utc", an IANA string, or a UTC offset
+   * https://moment.github.io/luxon/#/zones?id=specifying-a-zone
+   */
+  timezone?: "system" | string
 }
 
 export interface QuartzConfig {