From 1668c0dd6bce991a1457b53a653a39446d5b2916 Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Fri, 2 Oct 2026 16:02:11 +0200
Subject: [PATCH] feat: expose the tzdb version of the bundled zonefile

---
 scripts/tz/update.js    | 2 +-
 src/index.js            | 2 ++
 test/tzdb.test.js       | 9 +++++++++
 types/constructors.d.ts | 3 +++
 zonefile/_build.js      | 1 +
 zonefile/iana.js        | 1 +
 zonefile/pack.js        | 7 +++++--
 7 files changed, 22 insertions(+), 3 deletions(-)
 create mode 100644 test/tzdb.test.js

diff --git a/scripts/tz/update.js b/scripts/tz/update.js
index 8d89968..f9a41f4 100644
--- a/scripts/tz/update.js
+++ b/scripts/tz/update.js
@@ -187,7 +187,7 @@ export const main = (args = process.argv.slice(2)) => {
     tzdata: version,
     unsupported: unsupported.map((o) => o.name)
   })
-  const text = `// Generated by scripts/tz/update.js: ${source}\nexport default ${JSON.stringify(result, null, 2)}\n`
+  const text = `// Generated by scripts/tz/update.js: ${source}\nexport const tzdbVersion = ${JSON.stringify(version)}\nexport default ${JSON.stringify(result, null, 2)}\n`
   // Rename within the destination directory so readers never see a partial file.
   // Only remove a temporary file created by this run (exclusive creation may fail).
   const temporary = join(dirname(options.output), `.zonefile-${process.pid}.tmp`)
diff --git a/src/index.js b/src/index.js
index 504609c..8d8990b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,6 +1,7 @@
 import Spacetime from './spacetime.js'
 import whereIts from './whereIts.js'
 import version from './_version.js'
+import { tzdbVersion } from '../zonefile/_build.js'
 
 const main = (input, tz, options) => new Spacetime(input, tz, options)
 
@@ -62,6 +63,7 @@ main.min = function (tz, options) {
 //find tz by time
 main.whereIts = whereIts
 main.version = version
+main.tzdbVersion = tzdbVersion
 
 //aliases:
 main.plugin = main.extend
diff --git a/test/tzdb.test.js b/test/tzdb.test.js
new file mode 100644
index 0000000..a2ba321
--- /dev/null
+++ b/test/tzdb.test.js
@@ -0,0 +1,9 @@
+import test from 'tape'
+import spacetime from './lib/index.js'
+import { tzdbVersion } from '../zonefile/iana.js'
+
+test('tzdb version', (t) => {
+  t.ok(/^\d{4}[a-z]+$/.test(spacetime.tzdbVersion), `looks like '2026c'`)
+  t.equal(spacetime.tzdbVersion, tzdbVersion, 'same as zonefile/iana.js')
+  t.end()
+})
diff --git a/types/constructors.d.ts b/types/constructors.d.ts
index 7baf2f2..3326bcf 100644
--- a/types/constructors.d.ts
+++ b/types/constructors.d.ts
@@ -86,6 +86,9 @@ export interface SpacetimeStatic extends SpacetimeConstructor {
   /** list timezones by their time */
   whereIts: (a: string, b?: string) => string[]
 
+  /** IANA tzdb release of the bundled timezone data, like '2026c' */
+  tzdbVersion: string
+
   /** set as earliest-possible date */
   min: (timezone?: string, options?: SpacetimeConstructorOptions) => Spacetime
 
diff --git a/zonefile/_build.js b/zonefile/_build.js
index 86d49e2..ff5e5a9 100644
--- a/zonefile/_build.js
+++ b/zonefile/_build.js
@@ -1,3 +1,4 @@
+export const tzdbVersion = "2026c"
 export default {
   "9|s": "2/dili,2/jayapura",
   "9|n": "2/chita,2/khandyga,2/pyongyang,2/seoul,2/tokyo,2/yakutsk,11/palau,japan,rok",
diff --git a/zonefile/iana.js b/zonefile/iana.js
index 5b186c8..8eac5bc 100644
--- a/zonefile/iana.js
+++ b/zonefile/iana.js
@@ -1,3 +1,4 @@
+export const tzdbVersion = '2026c'
 export default {
   'africa/abidjan': {
     offset: 0,
diff --git a/zonefile/pack.js b/zonefile/pack.js
index 61f8f72..6717265 100644
--- a/zonefile/pack.js
+++ b/zonefile/pack.js
@@ -1,6 +1,6 @@
 //turn our timezone data into a small-as-possible string
 import { writeFileSync } from 'node:fs'
-import iana from './iana.js'
+import iana, { tzdbVersion } from './iana.js'
 import aliases from './aliases.js'
 import prefixes from './_prefixes.js'
 const all = {}
@@ -44,4 +44,7 @@ keys.forEach((k) => {
 })
 
 // console.log(result)
-writeFileSync('./zonefile/_build.js', 'export default ' + JSON.stringify(result, null, 2))
+writeFileSync(
+  './zonefile/_build.js',
+  `export const tzdbVersion = ${JSON.stringify(tzdbVersion)}\nexport default ${JSON.stringify(result, null, 2)}`
+)