# Svelte changelog
## Unreleased
* Fix inconsistencies when setting a two-way bound `` to `undefined` ([#3569](https://github.com/sveltejs/svelte/issues/3569))
* Fix resize listening on certain older browsers ([#4752](https://github.com/sveltejs/svelte/issues/4752))
* Add `a11y-no-onchange` warning ([#4788](https://github.com/sveltejs/svelte/pull/4788))
## 3.22.3
* Support default values and trailing commas in destructuring `{#await}` ([#4560](https://github.com/sveltejs/svelte/issues/4560), [#4810](https://github.com/sveltejs/svelte/issues/4810))
* Fix handling of `tweened` store when set using `duration: 0` ([#4799](https://github.com/sveltejs/svelte/issues/4799), [#4846](https://github.com/sveltejs/svelte/issues/4846))
* Fix setting `value` attribute with `bind:group` and attribute spread ([#4803](https://github.com/sveltejs/svelte/issues/4803))
* Fix issue with compound `{#if}` block involving static condition, dynamic condition, and inline component ([#4840](https://github.com/sveltejs/svelte/issues/4840))
* Update a11y warnings per ARIA 1.2 working draft ([#4844](https://github.com/sveltejs/svelte/issues/4844))
## 3.22.2
* Fix compiler exception with `a11y-img-redundant-alt` and value-less `alt` attribute ([#4777](https://github.com/sveltejs/svelte/issues/4777))
## 3.22.1
* Fix compiler exception with `a11y-img-redundant-alt` and dynamic `alt` attribute ([#4770](https://github.com/sveltejs/svelte/issues/4770))
## 3.22.0
* Fix misaligned line numbers in source maps ([#3906](https://github.com/sveltejs/svelte/issues/3906))
* Make setting a `tweened` store using `duration: 0` instantly update the value ([#4399](https://github.com/sveltejs/svelte/issues/4399))
* Fix reactivity with imported values that are then mutated ([#4555](https://github.com/sveltejs/svelte/issues/4555))
* Fix contextual dynamic `bind:this` inside `{#each}` block ([#4686](https://github.com/sveltejs/svelte/issues/4686))
* Do not display a11y warning about missing `href` for `` with `name` or `id` ([#4697](https://github.com/sveltejs/svelte/issues/4697))
* Disable infinite loop guard inside generators ([#4698](https://github.com/sveltejs/svelte/issues/4698))
* Display `a11y-invalid-attribute` warning for `href="javascript:..."` ([#4733](https://github.com/sveltejs/svelte/pull/4733))
* Implement `a11y-img-redundant-alt` warning ([#4750](https://github.com/sveltejs/svelte/pull/4750))
* Fix variable name conflict with component called `` ([#4768](https://github.com/sveltejs/svelte/issues/4768))
## 3.21.0
* Support dimension bindings in cross-origin environments ([#2147](https://github.com/sveltejs/svelte/issues/2147))
* Fix several related outro bugs ([#3202](https://github.com/sveltejs/svelte/issues/3202), [#3410](https://github.com/sveltejs/svelte/issues/3410), [#3685](https://github.com/sveltejs/svelte/issues/3685), [#4620](https://github.com/sveltejs/svelte/issues/4620), [#4630](https://github.com/sveltejs/svelte/issues/4630))
* Try using `globalThis` rather than `globals` for the benefit of non-Node servers and web workers ([#3561](https://github.com/sveltejs/svelte/issues/3561), [#4545](https://github.com/sveltejs/svelte/issues/4545))
* Support `{#await ... catch ...}` syntax shorthand ([#3623](https://github.com/sveltejs/svelte/issues/3623))
* Fix attaching of JS debugging comments to HTML comments ([#4565](https://github.com/sveltejs/svelte/issues/4565))
* Fix `` within `` ([#4597](https://github.com/sveltejs/svelte/issues/4597))
* Fix bug with updating simple `{#if}` blocks ([#4629](https://github.com/sveltejs/svelte/issues/4629))
* Fix issues with `` updates ([#4631](https://github.com/sveltejs/svelte/issues/4631), [#4687](https://github.com/sveltejs/svelte/issues/4687))
* Prevent illegal attribute names ([#4648](https://github.com/sveltejs/svelte/issues/4648))
* Fix `{#if}` block directly within `` ([#4703](https://github.com/sveltejs/svelte/issues/4703))
## 3.20.1
* Fix compiler regression with slots ([#4562](https://github.com/sveltejs/svelte/issues/4562))
## 3.20.0
* Allow destructuring in `{#await}` blocks ([#1851](https://github.com/sveltejs/svelte/issues/1851))
* Allow `` to be used in a slot ([#2798](https://github.com/sveltejs/svelte/issues/2798))
* Expose object of unknown props in `$$restProps` ([#2930](https://github.com/sveltejs/svelte/issues/2930))
* Prevent passing named slots other than from the top level within a component ([#3385](https://github.com/sveltejs/svelte/issues/3385))
* Allow transitions and animations to work within iframes ([#3624](https://github.com/sveltejs/svelte/issues/3624))
* Fix initialising slot fallbacks when unnecessary ([#3763](https://github.com/sveltejs/svelte/issues/3763))
* Disallow binding directly to `const` variables ([#4479](https://github.com/sveltejs/svelte/issues/4479))
* Fix re-attaching event handlers on keyed `{#each}` blocks ([#4491](https://github.com/sveltejs/svelte/issues/4491))
* Fix updating keyed `{#each}` blocks with `{:else}` ([#4536](https://github.com/sveltejs/svelte/issues/4536), [#4549](https://github.com/sveltejs/svelte/issues/4549))
* Fix hydration of top-level content ([#4542](https://github.com/sveltejs/svelte/issues/4542))
## 3.19.2
* In `dev` mode, display a runtime warning when a component is passed an unexpected slot ([#1020](https://github.com/sveltejs/svelte/issues/1020), [#1447](https://github.com/sveltejs/svelte/issues/1447))
* In `vars` array, correctly indicate whether `module` variables are `mutated` or `reassigned` ([#3215](https://github.com/sveltejs/svelte/issues/3215))
* Fix spread props not updating in certain situations ([#3521](https://github.com/sveltejs/svelte/issues/3521), [#4480](https://github.com/sveltejs/svelte/issues/4480))
* Use the fallback content for slots if they are passed only whitespace ([#4092](https://github.com/sveltejs/svelte/issues/4092))
* Fix bitmask overflow for `{#if}` blocks ([#4263](https://github.com/sveltejs/svelte/issues/4263))
* In `dev` mode, check for unknown props even if the component has no writable props ([#4323](https://github.com/sveltejs/svelte/issues/4323))
* Exclude global variables from `$capture_state` ([#4463](https://github.com/sveltejs/svelte/issues/4463))
* Fix bitmask overflow for slots ([#4481](https://github.com/sveltejs/svelte/issues/4481))
## 3.19.1
* Do not treat modifications to `$$props` as updates to a store called `$props` ([#4368](https://github.com/sveltejs/svelte/issues/4368))
* Deconflict `value` parameter name used in contextual bindings ([#4445](https://github.com/sveltejs/svelte/issues/4445))
* Fix dev mode validation of `{#each}` blocks using strings ([#4450](https://github.com/sveltejs/svelte/issues/4450))
## 3.19.0
* Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
* `$capture_state`/`$inject_state` now act on the component's entire state, rather than its props ([#3822](https://github.com/sveltejs/svelte/pull/3822))
* Warn when using `` and `Foo` is dynamic ([#4331](https://github.com/sveltejs/svelte/issues/4331))
* Display compilation warnings in `svelte/register` in dev mode ([#4364](https://github.com/sveltejs/svelte/issues/4364))
* Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))
* Throw runtime error in dev mode for non-array-like values in `{#each}` blocks ([#4408](https://github.com/sveltejs/svelte/issues/4408))
## 3.18.2
* Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
* Improve parsing error messages when there is a pending unclosed tag ([#4131](https://github.com/sveltejs/svelte/issues/4131))
* Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
* Improve performance of `flush()` by not using `.shift()` ([#4356](https://github.com/sveltejs/svelte/pull/4356))
* Permit reserved keywords as destructuring keys in `{#each}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
* Disallow reserved keywords in `{expressions}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
* Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
* Fix event handlers that are dynamic via reactive declarations or stores ([#4388](https://github.com/sveltejs/svelte/issues/4388))
* Fix invalidation in expressions like `++foo.bar` ([#4393](https://github.com/sveltejs/svelte/issues/4393))
## 3.18.1
* Fix code generation error with adjacent inline and block comments ([#4312](https://github.com/sveltejs/svelte/issues/4312))
* Fix detection of unused CSS selectors that begin with a `:global()` but contain a scoped portion ([#4314](https://github.com/sveltejs/svelte/issues/4314))
## 3.18.0
* Fix infinite loop when instantiating another component during `onMount` ([#3218](https://github.com/sveltejs/svelte/issues/3218))
* Make autosubscribing to a nullish store a no-op ([#2181](https://github.com/sveltejs/svelte/issues/2181))
## 3.17.3
* Fix updating a `` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
* Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
* Add dev mode check to disallow duplicate keys in a keyed `{#each}` ([#4301](https://github.com/sveltejs/svelte/issues/4301))
* Fix hydration of `` when starting from SSR-generated code with `hydratable: true` ([#4310](https://github.com/sveltejs/svelte/issues/4310))
## 3.17.2
* Fix removing attributes during hydration ([#1733](https://github.com/sveltejs/svelte/issues/1733))
* Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
* Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
* Fix `~=` and class selector matching against values separated by any whitespace characters ([#4242](https://github.com/sveltejs/svelte/issues/4242))
* Fix code generation for `await`ed expressions that need parentheses ([#4267](https://github.com/sveltejs/svelte/issues/4267))
* Preserve JavaScript comments from the original component source where possible ([#4268](https://github.com/sveltejs/svelte/issues/4268))
* Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
* Correctly apply event modifiers to `` events ([#4278](https://github.com/sveltejs/svelte/issues/4278))
## 3.17.1
* Only attach SSR mode markers to a component's `` elements when compiling with `hydratable: true` ([#4258](https://github.com/sveltejs/svelte/issues/4258))
## 3.17.0
* Remove old `` elements during hydration so they aren't duplicated ([#1607](https://github.com/sveltejs/svelte/issues/1607))
* Prevent text input cursor jumping in Safari with one-way binding ([#3449](https://github.com/sveltejs/svelte/issues/3449))
* Expose compiler version in dev events ([#4047](https://github.com/sveltejs/svelte/issues/4047))
* Don't run actions before their element is in the document ([#4166](https://github.com/sveltejs/svelte/issues/4166))
* Fix reactive assignments with destructuring and stores where the destructured value should be undefined ([#4170](https://github.com/sveltejs/svelte/issues/4170))
* Fix hydrating `{:else}` in `{#each}` ([#4202](https://github.com/sveltejs/svelte/issues/4202))
* Do not automatically declare variables in reactive declarations when assigning to a member expression ([#4212](https://github.com/sveltejs/svelte/issues/4212))
* Fix stringifying of attributes in SSR mode when there are spread attributes ([#4240](https://github.com/sveltejs/svelte/issues/4240))
* Only render one `` in SSR mode when multiple components provide one ([#4250](https://github.com/sveltejs/svelte/pull/4250))
## 3.16.7
* Also apply actions in the order they're given along with other directives ([#2446](https://github.com/sveltejs/svelte/issues/2446), [#4156](https://github.com/sveltejs/svelte/pull/4156))
* Check whether a dynamic event handler is a function before calling it ([#4090](https://github.com/sveltejs/svelte/issues/4090))
* Correctly mark event handlers as dynamic when they involve an expression used in a `bind:` elsewhere ([#4155](https://github.com/sveltejs/svelte/pull/4155))
## 3.16.6
* Fix CSS specificity bug when encapsulating styles ([#1277](https://github.com/sveltejs/svelte/issues/1277))
* Apply directives in the order they're given ([#2446](https://github.com/sveltejs/svelte/issues/2446))
* Fix destructuring in `let:` directives ([#2751](https://github.com/sveltejs/svelte/issues/2751))
* Preserve whitespace around ``s in `