Can async derived values be fixed to avoid infinite loops and reactivity issues? new
13 people asked· svelte · since May 31, 2026
With compilerOptions.experimental.async enabled, if state is invalidated while an async derived is still pending (so more than one Batch is alive), $derived values lose their …
Can the compiler preserve parentheses in logical expressions? new
6 people asked· svelte · since Jun 3, 2026
When using rune mode in a `.svelte` or `.svelte.ts` file, the `!==` binary operator is incorrectly compiled so that the resulting `$.strict_equals()` call receives the …
When the Svelte compiler re-prints a JavaScript logical expression that contains a **parenthesized `||` (or `&&`) nested on the side that needs the parentheses**, it …
Can declaration tags support multiple declarators and fix binding issues? new
5 people asked· svelte · since May 30, 2026
Consider the following Child component Consider the Main svelte file Throws the following error `Can't find variable: labelKey in <unknown> in Child.svelte in App.svelte in …
When you attempt to shadow a known variable in `{const variable = ...}` declaration tag it errors. [REPL](https://svelte.dev/playground/hello-world?version=5.56.4#H4sIAAAAAAAA …
const} is considered legacy and {const} should be used as replacement: * https://svelte.dev/docs/svelte/@const * https://sveltejs.github.io/eslint-plugin-svelte/rules/no-at-co …
Can the compiler support TypeScript and improve type handling? new
5 people asked· svelte · since May 31, 2026
Svelte 5.35.0+ appears to preserve the TypeScript optional parameter marker (`?`) in generated JavaScript for optional function parameters inside `<script lang="ts">`. Valid S …
When exporting snippets referencing the type of a value from the regular `<script>` block, the TypeScript error: is thrown instead of the expected error: > …
If the vscode setting `js/ts.inlayHints.parameterNames.enabled` is set to `all` and there are attributes before an `{@attach ...}` on an element, the hints gets displayed insi …
We have also been continually running into the freezing issue, i've tested it against this PR and it seems to disappear completely. @dummdidumm what's the …
Can I fix whitespace behavior attributed to Bun instead of Svelte? new
4 people asked· svelte · since Aug 18, 2026
The compiler printer drops a meaningful whitespace text node after an inline element. This changes the rendered text from `Hello bold world` to `Hello boldworld`. …
thank you, can this be expanded to fix text-node whitespace similar issue where result drops all white spaces. svelte version: 5.56.10 INPUT : `"<p>Hello < …
I expect `<input defaultValue="foo" />` to SSR as `<input value="foo"/>`, but it instead renders as `<input/>`. This means on pages without JS, the default …
there is a note in https://svelte.dev/docs/kit/configuration#csp about usage of svelte transitions: > Note that most Svelte transitions work by creating an …
Why is regex-based preprocessor parsing unreliable? new
2 people asked· svelte · since Jul 28, 2026
That's fair. I understand not wanting to have the regex turn into something unmaintainable. I did some basic searching and could not find any related …
Previously, we've said that it is components' responsibility to not contain code that's going to confuse the dumb regex-based parsing of preprocessors if the …
Can async derived values be fixed to avoid infinite loops and reactivity issues? new
13 people asked· since May 31, 2026
With compilerOptions.experimental.async enabled, if state is invalidated while an async derived is still pending (so more than one Batch is alive), $derived values lose their …
Can the compiler preserve parentheses in logical expressions? new
6 people asked· since Jun 3, 2026
When using rune mode in a `.svelte` or `.svelte.ts` file, the `!==` binary operator is incorrectly compiled so that the resulting `$.strict_equals()` call receives the …
When the Svelte compiler re-prints a JavaScript logical expression that contains a **parenthesized `||` (or `&&`) nested on the side that needs the parentheses**, it …
Can declaration tags support multiple declarators and fix binding issues? new
5 people asked· since May 30, 2026
Consider the following Child component Consider the Main svelte file Throws the following error `Can't find variable: labelKey in <unknown> in Child.svelte in App.svelte in …
When you attempt to shadow a known variable in `{const variable = ...}` declaration tag it errors. [REPL](https://svelte.dev/playground/hello-world?version=5.56.4#H4sIAAAAAAAA …
const} is considered legacy and {const} should be used as replacement: * https://svelte.dev/docs/svelte/@const * https://sveltejs.github.io/eslint-plugin-svelte/rules/no-at-co …
Can the compiler support TypeScript and improve type handling? new
5 people asked· since May 31, 2026
Svelte 5.35.0+ appears to preserve the TypeScript optional parameter marker (`?`) in generated JavaScript for optional function parameters inside `<script lang="ts">`. Valid S …
When exporting snippets referencing the type of a value from the regular `<script>` block, the TypeScript error: is thrown instead of the expected error: > …
If the vscode setting `js/ts.inlayHints.parameterNames.enabled` is set to `all` and there are attributes before an `{@attach ...}` on an element, the hints gets displayed insi …
We have also been continually running into the freezing issue, i've tested it against this PR and it seems to disappear completely. @dummdidumm what's the …
Can I fix whitespace behavior attributed to Bun instead of Svelte? new
4 people asked· since Aug 18, 2026
The compiler printer drops a meaningful whitespace text node after an inline element. This changes the rendered text from `Hello bold world` to `Hello boldworld`. …
thank you, can this be expanded to fix text-node whitespace similar issue where result drops all white spaces. svelte version: 5.56.10 INPUT : `"<p>Hello < …
I expect `<input defaultValue="foo" />` to SSR as `<input value="foo"/>`, but it instead renders as `<input/>`. This means on pages without JS, the default …
there is a note in https://svelte.dev/docs/kit/configuration#csp about usage of svelte transitions: > Note that most Svelte transitions work by creating an …
Why is regex-based preprocessor parsing unreliable? new
2 people asked· since Jul 28, 2026
That's fair. I understand not wanting to have the regex turn into something unmaintainable. I did some basic searching and could not find any related …
Previously, we've said that it is components' responsibility to not contain code that's going to confuse the dumb regex-based parsing of preprocessors if the …
Why does onDestroy crash on server-side rendering? new
2 people asked· since Aug 8, 2026
This is expected and documented - onDestroy indeed does run on the server precisely so that you can cleanup things on the server, too. https://svelte.dev/ …
When you use onDestroy function inside +page.svelte or +layout.svelte, the callback runs on the server and causes crash. While at the same time, a callback …
Can I fix the print function dropping CSS escape sequences? new
2 people asked· since Aug 18, 2026
print()` drops CSS escape sequences from selectors, so a stylesheet that `parse()` accepts can come back either invalid or meaning something different. Using the repo's …
print()` drops CSS escape sequences from selectors, so a stylesheet that `parse()` accepts can come back either invalid or meaning something different. Using the repo's …
Can hydration mismatches with async derived and bind be fixed? new
1 person asked· since Jun 7, 2026
Please see the attached minimal example project. Reproduces reliably. It's just 24 lines. Thanks!! [svelte hydration bug.zip](https://github.com/user-attachments/files/2868898 …
Can bind:value be fixed to not reset selection on custom select? new
1 person asked· since May 31, 2026
When a `<select>` uses the customizable-select API (`appearance: base-select`) and contains the author trigger `<button><selectedcontent></selectedcontent></button>`, adding ` …
Can infinite loops with const ending with bare slash be prevented? new
1 person asked· since Jun 1, 2026
I found this issue while working on https://github.com/sveltejs/svelte/pull/18330. This hang can be particularly problematic when it occurs in the language …
Can the documentation clarify that bare const is not reactive like @const? new
1 person asked· since Jun 1, 2026
The [declaration-tags docs](https://svelte.dev/docs/svelte/declaration-tags) say `{@const ...}` is legacy and to use `{const ...}` instead, but don't mention that the two …
Can batch roots error when sibling mutates shared state be fixed? new
1 person asked· since Jun 2, 2026
Full disclosure: the debugging here was largely done by Claude, reviewed by me (an experienced backend SWE who doesn't know Svelte internals deeply). The bug …
Can $state.eager behavior in if blocks be clarified? new
1 person asked· since Jun 2, 2026
In [this playground](https://svelte.dev/playground/hello-world?version=5.56.1#H4sIAAAAAAAACm2QMW-EMAyF_0rO7QASOriOCJC6dezQremQA1OiBgclprSK-O9Vgk5dbrGlT8_vPTkAqRmhhhc0xorNOjOID …
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