Typescript errors: RolldownError: Parse failure: Parse failed with 1 error:

[sorinpopescu]

Description

On the build time or page load it fails because of date in more packages.

`Error: Error during dependency optimization:

Build failed with 3 errors:

[PARSE_ERROR] Expected , or ) but found ?
╭─[ node_modules/.pnpm/flowbite-svelte@1.33.1_rollup@4.62.2_svelte@5.56.3_tailwindcss@4.3.1/node_modules/flowbite-svelte/dist/datepicker/Datepicker.svelte:458:26 ]
│
458 │ const formatDate = (date?) => date?.toLocaleDateString(locale(), $$props.dateFormat) ?? "";
│ ┬ ┬
│ ╰─────── Opened here
│ │
│ ╰── , or ) expected
─────╯

[PARSE_ERROR] Expected , or ) but found ?
╭─[ node_modules/.pnpm/flowbite-svelte@1.33.1_rollup@4.62.2_svelte@5.56.3_tailwindcss@4.3.1/node_modules/flowbite-svelte/dist/command-palette/CommandPalette.svelte:79:20 ]
│
79 │ const check = (x?) => x?.toLowerCase().includes(searchLower);
│ ┬ ┬
│ ╰──── Opened here
│ │
│ ╰── , or ) expected
────╯

[PARSE_ERROR] Expected , or ) but found ?
╭─[ node_modules/.pnpm/flowbite-svelte@1.33.1_rollup@4.62.2_svelte@5.56.3_tailwindcss@4.3.1/node_modules/flowbite-svelte/dist/scroll-spy/ScrollSpy.svelte:97:40 ]
│
97 │ function scrollToSection(itemId, event?) {
│ ┬ ┬
│ ╰──────────────── Opened here
│ │
│ ╰── , or ) expected
────╯

at aggregateBindingErrorsIntoJsError (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/shared/error-BuvQYXuZ.mjs:48:18)
at unwrapBindingResult (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/shared/error-BuvQYXuZ.mjs:18:128)
at #build (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/shared/rolldown-build-CrPk_lZe.mjs:3246:34)
at async Object.build (file:///app/node_modules/.pnpm/vite@8.0.16_@types+node@26.0.0_jiti@2.7.0/node_modules/vite/dist/node/chunks/node.js:31848:11) {

errors: [Getter/Setter]
}`

Minimal Reproduction

No code related.
The error appear at:
- build
- page run

I have try to downgrade vite to 7 - same.
Upgrade to floabite svelte 2
Clean tsconfig
And more

Steps to Reproduce

Clean project

Environment

System:
    OS: Linux 6.1 Debian GNU/Linux 13 (trixie) 13 (trixie)
    CPU: (16) x64 Intel Xeon Processor (Skylake, IBRS, no TSX)
    Memory: 17.94 GB / 30.60 GB
    Container: Yes
    Shell: 5.2.37 - /bin/bash
  Binaries:
    Node: 26.3.1 - /usr/local/bin/node
    npm: 11.16.0 - /usr/local/bin/npm
    pnpm: 11.8.0 - /usr/local/bin/pnpm
  npmPackages:
    @sveltejs/kit: ^2.66.0 => 2.66.0 
    flowbite: ^4.0.2 => 4.0.2 
    flowbite-svelte: ^1.33.1 => 1.33.1 
    svelte: ^5.56.3 => 5.56.3 
    vite: ^8.0.16 => 8.0.16

Relevant Logs / Console Output

[500] GET /user/login
RolldownError: Parse failure: Parse failed with 1 error:
Expected `,` or `)` but found `?`
336: 
337:       // Use locale for formatting (not finalTranslationLocale)
338:       const formatDate = (date?) => date?.toLocaleDateString(locale, dateFormat) ?? "";
                                   ^
339: 
340:       const isSameDate = (date1?, date2?) => date1 && date2 ? isSameDay(date1, date2) : false;
336: 
337:       // Use locale for formatting (not finalTranslationLocale)
338:       const formatDate = (date?) => date?.toLocaleDateString(locale, dateFormat) ?? "";
                              ^
339: 
340:       const isSameDate = (date1?, date2?) => date1 && date2 ? isSameDay(date1, date2) : false;
At file: /node_modules/.pnpm/flowbite-svelte@1.33.1_rollup@4.62.2_svelte@5.56.3_tailwindcss@4.3.1/node_modules/flowbite-svelte/dist/datepicker/Datepicker.svelte?v=1fd87802:338:27
    at error (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/shared/logs-aMKUxRpj.mjs:147:24)
    at normalizeParseError (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/parse-ast-index.mjs:25:9)
    at wrap (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/parse-ast-index.mjs:5:39)
    at parseAstAsync (file:///app/node_modules/.pnpm/rolldown@1.0.3/node_modules/rolldown/dist/parse-ast-index.mjs:54:9)
    at async ssrTransformScript (file:///app/node_modules/.pnpm/vite@8.0.16_@types+node@26.0.0_jiti@2.7.0/node_modules/vite/dist/node/chunks/node.js:11179:9)
    at async loadAndTransform (file:///app/node_modules/.pnpm/vite@8.0.16_@types+node@26.0.0_jiti@2.7.0/node_modules/vite/dist/node/chunks/node.js:24680:64)

Screenshots / GIF (optional)

No response

Additional Context (optional)

Pakage.json
`
{
"name": "blb",
"private": true,
"version": "1.0.1",
"type": "module",
"scripts": {
"dev": "vite dev --host",
"build": "vite build",
"preview": "vite preview",
"prepare": "svelte-kit sync || echo ''",
"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch"
},
"devDependencies": {
"@sveltejs/adapter-node": "^5.5.4",
"@sveltejs/kit": "^2.66.0",
"@sveltejs/vite-plugin-svelte": "^7.1.2",
"@tailwindcss/vite": "^4.3.1",
"@types/node": "^26.0.0",
"flowbite": "^4.0.2",
"flowbite-svelte": "^1.33.1",
"flowbite-svelte-icons": "^3.1.0",
"svelte": "^5.56.3",
"svelte-check": "^4.6.0",
"tailwindcss": "^4.3.1",
"typescript": "^6.0.3",
"vite": "^8.0.16"
},
"dependencies": {
"jose": "^6.2.3",
"tailwind-variants": "^3.2.2"
}
}

`

Vite config

`import tailwindcss from '@tailwindcss/vite';
import { sveltekit } from '@sveltejs/kit/vite';
import { defineConfig } from 'vite';

export default defineConfig({
plugins: [
tailwindcss(),
sveltekit()
],
optimizeDeps: {
exclude: [
'flowbite-svelte',
'flowbite-svelte-icons'
]
},
ssr: {
noExternal: [
'flowbite-svelte',
'flowbite-svelte-icons'
]
},
server: {
allowedHosts: ['localhost']
}
});
`

Checklist

• I have searched existing issues and discussions
• I have provided a minimal and runnable reproduction
• I am using the latest version of Flowbite-Svelte

[sorinpopescu]

I have created 2 patches one for 1.33.1 and one for 2.0 as both looks affected.
With both works as expected and the errors are gone.
Attached the zips.

flowbite-svelte@1.33.1.patch.zip
flowbite-svelte@2.0.0-next.14.patch.zip

[shinokada]

@sorinpopescu Can you create a PR so that I can see diff?

[sorinpopescu]

@shinokada I like to, but I do not have the repo setup and do not have time right now.
I put here from the file. Those are not big changes.
I hope that helps.

`--- a/dist/datepicker/Datepicker.svelte
+++ b/dist/datepicker/Datepicker.svelte
@@ -304,8 +304,8 @@
}

// Use locale for formatting (not finalTranslationLocale)

• const formatDate = (date?: Date): string => date?.toLocaleDateString(locale, dateFormat) ?? "";
• const isSameDate = (date1?: Date, date2?: Date): boolean => (date1 && date2 ? isSameDay(date1, date2) : false);

• const formatDate = (date: Date | undefined = undefined): string => date?.toLocaleDateString(locale, dateFormat) ?? "";
• const isSameDate = (date1: Date | undefined = undefined, date2: Date | undefined = undefined): boolean => (date1 && date2 ? isSameDay(date1, date2) : false);
  const isToday = (day: Date): boolean => isSameDate(day, new Date());
  const isInRange = (day: Date): boolean => !!(range && rangeFrom && rangeTo && isWithinInterval(day, { start: rangeFrom, end: rangeTo }));`

`--- a/dist/command-palette/CommandPalette.svelte
+++ b/dist/command-palette/CommandPalette.svelte
@@ -33,7 +33,7 @@
const searchLower = search.trim().toLowerCase();
if (searchLower === "") return items;

• const check = (x?: string) => x?.toLowerCase().includes(searchLower);

• const check = (x: string | undefined = undefined) => x?.toLowerCase().includes(searchLower);
  return items.filter((item) => check(item.label) || check(item.description) || item.keywords?.some(check));
  });`

`--- a/dist/scroll-spy/ScrollSpy.svelte
+++ b/dist/scroll-spy/ScrollSpy.svelte
@@ -64,7 +64,7 @@
return clsx(link, customClass);
}

• function scrollToSection(itemId: string, event?: MouseEvent) {

• function scrollToSection(itemId: string, event: MouseEvent | undefined = undefined) {
  if (!browser) return;

  if (event) event.preventDefault();`

[abart27]

Can repro on 1.33.1

[kingjan1999]

Updating to svelte 5.56.4+ fixed this for me (per sveltejs/vite-plugin-svelte#1360 (comment))