use tinyduration for ISO8601 parsing and serializing

package.json

@@ -40,12 +40,12 @@
 	},
 	"peerDependencies": {
 		"@sveltejs/kit": "^2.20.2",
-		"svelte": "^5.0.0",
-		"tailwindcss": "^4.1.11",
-		"tailwindcss-animate": "^1.0.7",
 		"@tailwindcss/container-queries": "^0.1.1",
 		"@tailwindcss/forms": "^0.5.10",
-		"@tailwindcss/vite": "^4.1.11"
+		"@tailwindcss/vite": "^4.1.11",
+		"svelte": "^5.0.0",
+		"tailwindcss": "^4.1.11",
+		"tailwindcss-animate": "^1.0.7"
 	},
 	"dependencies": {
 		"@internationalized/date": "^3.8.2",
@@ -56,7 +56,8 @@
 		"match-sorter": "^8.0.0",
 		"melt": "^0.37.0",
 		"moment": "^2.30.1",
-		"phosphor-svelte": "^3.0.1"
+		"phosphor-svelte": "^3.0.1",
+		"tinyduration": "^3.4.1"
 	},
 	"devDependencies": {
 		"@eslint/compat": "^1.2.5",

pnpm-lock.yaml

@@ -59,6 +59,9 @@ importers:
       tailwindcss-animate:
         specifier: ^1.0.7
         version: 1.0.7(tailwindcss@4.1.11)
+      tinyduration:
+        specifier: ^3.4.1
+        version: 3.4.1
     devDependencies:
       '@eslint/compat':
         specifier: ^1.2.5
@@ -1539,6 +1542,9 @@ packages:
     resolution: {integrity: sha512-5S7Va8hKfV7W5U6g3aYxXmlPoZVAwUMy9AOKyF2fVuZa2UD3qZjg578OrLRt8PcNN1PleVaL/5/yYATNL0ICUw==}
     engines: {node: '>=18'}
 
+  tinyduration@3.4.1:
+    resolution: {integrity: sha512-NemFoamVYn7TmtwZKZ3OiliM9fZkr6EWiTM+wKknco6POSy2gS689xx/pXip0JYp40HXpUw6k65CUYHWYUXdaA==}
+
   tinyglobby@0.2.14:
     resolution: {integrity: sha512-tX5e7OM1HnYr2+a2C/4V0htOcSQcoSTH9KgJnVvNm5zm/cyEWKJ7j7YutsH9CxMdtOkkLFy2AHrMci9IM8IPZQ==}
     engines: {node: '>=12.0.0'}
@@ -2917,6 +2923,8 @@ snapshots:
       mkdirp: 3.0.1
       yallist: 5.0.0
 
+  tinyduration@3.4.1: {}
+
   tinyglobby@0.2.14:
     dependencies:
       fdir: 6.4.6(picomatch@4.0.3)

src/lib/DurationInput.svelte

@@ -26,12 +26,7 @@
 	 * @returns The ISO 8601 duration string.
 	 */
 	export const durationToISO8601 = (duration: TimeDuration): string => {
-		let str = 'P';
+		return serialize(duration);
-		if (duration.hours || duration.minutes || duration.seconds) str += 'T';
-		if (duration.hours) str += `${duration.hours}H`;
-		if (duration.minutes) str += `${duration.minutes}M`;
-		if (duration.seconds) str += `${duration.seconds}S`;
-		return str;
 	};
 
 	/**
@@ -40,16 +35,7 @@
 	 * @returns The TimeDuration object.
 	 */
 	export const iso8601ToDuration = (str: string): TimeDuration => {
-		const regex = /^P(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?$/;
+		return parse(str);
-		const matches = str.match(regex);
-		if (!matches) {
-			throw new Error('Invalid ISO 8601 duration string');
-		}
-		return {
-			hours: matches[2] ? parseInt(matches[2], 10) : 0,
-			minutes: matches[3] ? parseInt(matches[3], 10) : 0,
-			seconds: matches[4] ? parseInt(matches[4], 10) : 0
-		};
 	};
 </script>
 
@@ -62,6 +48,7 @@
 	import Label from './Label.svelte';
 	import { liveValidator, validate } from '@svelte-toolkit/validate';
 	import StyledRawInput from './StyledRawInput.svelte';
+	import { parse, serialize } from 'tinyduration';
 
 	interface Props {
 		/**