### Before submitting the PR, please make sure you do the following
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`$state.snapshot` already clones the value returned from `toJSON`, and
its `Snapshot<T>` type reflects that return type. The `$state.snapshot`
docs now call out that behavior explicitly, including the generated
ambient types shown by editors.
Test plan: `pnpm check`; `pnpm lint`.
Fixes#18129
Co-authored-by: sakaenyeniceri5 <sakaenyeniceri5@users.noreply.github.com>
## Summary
- Fix the missing space before `<option>` in the bind documentation.
## Related issue
- N/A
## Guideline alignment
- Read `CONTRIBUTING.md` and kept this to one focused docs-only file
change.
- No behavior, test, fixture, changeset, or generated-file changes.
## Test plan
- `git diff --check`
- Not run: docs-only spacing fix.
Co-authored-by: Codex <codex@openai.com>
Per
https://github.com/sveltejs/svelte/pull/17862#issuecomment-4049752548,
this freezes the value of a derived if it was created inside a parent
effect that is now destroyed. This prevents the sort of bug where a
derived reads `foo.bar` even though `foo` is now `undefined`.
If the derived is dirty, a warning will be printed.
This PR also gets rid of some weirdness around `derived.parent` — it can
only ever be an `Effect | null`, and there's no need for
`get_derived_parent_effect`.
Blocked on https://github.com/sveltejs/kit/pull/15533 and a follow-up
that switches remote functions to use `$effect.root` (since this
effectively undoes #17171), hence draft.
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---------
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Adds documentation for using CSS custom properties with the `style:`
directive. I think this was lost at some point during the great
transition. It's only mentioned in the [best
practices](https://svelte.dev/docs/svelte/best-practices#Using-JavaScript-variables-in-CSS)
section, so I thought it would make sense to include it.
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### Tests and linting
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---------
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Co-authored-by: Rich Harris <rich.harris@vercel.com>
## Description
**While investigating the compiler analysis phase for errors or missing
lines, I located an explicit `TODO fix the message here` comment in the
source code
(`packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js`).**
### Triggering Code
```svelte
<script module>
import { foo } from './somewhere.js';
</script>
<script>
let foo = 'conflict'; // Triggers the duplicate module import error
</script>
```
## The Bug
When a component author creates a local `let` declaration in the
instance `<script>` block that shadows a variable imported in the
`<script module>` block, the compiler emits a
`declaration_duplicate_module_import` error.
However, the error message text was misleading. It stated:
```diff
- Cannot declare a variable with the same name as an import inside `<script module>`
+ Cannot declare a variable with the same name as an import from `<script module>`
```
This incorrectly implies that the duplicate declaration itself is
happening *inside* the module script block, rather than colliding with
an import *from* that block.
## Changes Made
| Action | Target (File / Function) | Description |
| :--- | :--- | :--- |
| **Template Fix** | `packages/svelte/messages/compile-errors/script.md`
| Changed "inside" to "from" to accurately reflect the nature of the
shadow collision. |
| **Regenerated Errors** | `packages/svelte/src/compiler/errors.js` |
Ran `pnpm generate` to apply the updated markdown template into the
dictionary list. |
| **Removed TODO** | `ensure_no_module_import_conflict` function |
Removed the original `// TODO fix the message here` notation from the
validator. |
| **Test Adjustments** | `illegal-variable-declaration/errors.json` |
Updated the validator test suite snapshots to assert against the correct
error message format. |
## Validation Results
* The error correctly throws when a user replicates this component
structure.
* Vitest suite `tests/validator/test.ts` successfully asserts the new,
clearer message.
---
### Before submitting the PR, please make sure you do the following
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# THANK YOU
This takes advantage of https://github.com/sveltejs/svelte.dev/pull/1879
and https://github.com/sveltejs/svelte.dev/pull/1880 to replace some of
the hardcoded playground links in the docs with ones that are generated
automatically from the code. This is a better user experience, and
easier to maintain.
Not every playground link is suitable for replacement, as in many cases
we gloss over implementation details. For now I'm just starting with
some easy ones
Closes#17660
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### Tests and linting
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
### Before submitting the PR, please make sure you do the following
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discussed ahead of time. In many cases, features are absent for a
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it.
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changeset (`npx changeset`).
### Tests and linting
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
With this, we can add invariants to the codebase so we can identify
problems like 'this batch already has roots scheduled', which indicate a
bug somewhere, without a) needing tests for scenarios that are
inherently hard to anticipate, or b) cluttering people's prod bundles
### Summary
Fix spelling in the v5 migration guide ("useable" -> "usable").
### Before submitting the PR, please make sure you do the following
- [ ] It's really useful if your PR references an issue where it is
discussed ahead of time. In many cases, features are absent for a
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it.
- [ ] If this PR changes code within `packages/svelte/src`, add a
changeset (`npx changeset`). (Not applicable; docs-only change.)
### Tests and linting
- [ ] Run the tests with `pnpm test` and lint the project with `pnpm
lint`. (Not run; docs-only change.)
Co-authored-by: rohan436 <rohan.santhoshkumar@googlemail.com>
This adds a `skill: true` to the frontmatter of the bestpractices
skill/doc. This way when we sync we can concern ourselves to only the
documents that need to be skills (we will write one for sveltekit too)
without targeting specific files in the `ai-tools` repo
Based on #17727 but with a few changes:
- smaller (fewer tokens)
- removed some bits that are really just summarising existing docs
- added an explicit 'don't use these legacy features' section
- shuffled some things around a bit
---------
Co-authored-by: paoloricciuti <ricciutipaolo@gmail.com>
Co-authored-by: Federico Varano <50919335+fvarano@users.noreply.github.com>
Co-authored-by: ComputerGuy <63362464+Ocean-OS@users.noreply.github.com>
Hi!
I run into this issue today, and found the fix in
https://github.com/sveltejs/svelte/issues/16680#issuecomment-3229435832
I thought it would be a nice addition to the documentation (it's where I
looked first)
### Before submitting the PR, please make sure you do the following
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---------
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Repository https://github.com/sveltejs/template is archived and no
longer maintained.
### Before submitting the PR, please make sure you do the following
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it.
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---------
Co-authored-by: Rich Harris <hello@rich-harris.dev>
## Motivation
noticed that the documentation for the `<svelte:document>` still refers
to actions - probably would be better for beginners if it referred to
the newer attachments instead.
### Before submitting the PR, please make sure you do the following
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This makes error boundaries run on the server if a new `onerror` handler
is passed to `render`. `onerror` can either synchronously or
asynchronously return a value. It should be a sanitized
JSON.stringify-able value so that it can be passed to the client for
hydration via a comment. `mount/hydrate` also get the `onerror`
property.
If no `onerror` is passed to `render` it will just throw just like
before, hence this is backwards compatible.
This work is important for SvelteKit to allow `+error.svelte` to make
use of them and in general to make boundaries properly work during SSR
(also see https://github.com/sveltejs/kit/issues/14398).
closes#15370
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---------
Co-authored-by: Rich Harris <rich.harris@vercel.com>
## Summary
Fixes#17721
In dev mode, detect when a keyed each block has a key function that
returns different values when called multiple times for the same item
(non-idempotent). This catches the common mistake of using array
literals like `[thing.group, thing.id]` as keys, which creates a new
array object each time and will never match by reference.
- Adds new `each_key_volatile` error with helpful message explaining the
issue
- Checks key idempotency in the each block loop during dev mode
- Provides a clear error instead of the cryptic "Cannot read properties
of undefined" that occurred previously
---------
Co-authored-by: 7nik <kifiranet@gmail.com>
Remove `onwheel` and `onmousewheel` from the list of passive events
in the v5 migration guide. Since #13322, only `ontouchstart` and
`ontouchmove` are passive by default, matching the basic-markup docs.
Closes#17430
* docs: add note about typing children as Snippet in \$props
* Apply suggestion from @Rich-Harris
* Apply suggestion from @Rich-Harris
---------
Co-authored-by: gokul.d <gokul.d@juspay.in>
Co-authored-by: Rich Harris <hello@rich-harris.dev>
Paolo Ricciuti
Rich Harris
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Rohan Santhosh Kumar
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