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🎅🎄🎁 ADVENT OF SVELTE 🎅🎄🎁 We're going to ship one thing a day every day from now until Christmas. Wish us luck! svelte.dev/blog/advent-... First up...

Day 1 — error boundaries! Wrap your code in a <svelte:boundary> and you can isolate and recover from unexpected errors. 🎁 docs svelte.dev/docs/svelte/... 🎁 tutorial svelte.dev/tutorial/sve...

Day 2 — `each` without `as`, for when you just want lots of one thing - docs svelte.dev/docs/svelte/... - demo svelte.dev/playground/e...

Day 3 — you can now export snippets from a <script module> (terms and conditions apply) - docs svelte.dev/docs/svelte/... - demo svelte.dev/playground/1...

Day 4 — specify a `defaultValue` on form inputs, and it will be used when the form is reset - docs svelte.dev/docs/svelte/... - demo svelte.dev/playground/b...

Day 5 — it's a three-in-one kind of day! `new MediaQuery(...)` lets you use media queries reactively. prefersReducedMotion is an instance of MediaQuery that makes it easier to respect users' accessibility preferences - docs svelte.dev/docs/svelte/... - demo svelte.dev/playground/8... there's more!

Day 5, part two — the MediaQuery stuff is powered by createSubscriber, which is an advanced feature mainly for library authors. It makes it easy for you to build your own reactive classes that set up event listeners when something is read inside an effect. - docs svelte.dev/docs/svelte/...

Day 7 — the first of a few planned improvements to the site. A lot of you (rightly!) disliked the tutorial dropdown navigation, so we fixed it. You can even navigate the tutorial with JS disabled, if you're so inclined 🎁 svelte.dev/tutorial

Day 8 — we're calling this 'function bindings'. You know how you can do `bind:value={value}`? You can now do this... bind:value={getValue, setValue} ...which lets you transform and validate data 🎁 docs svelte.dev/docs/svelte/... 🎁 demo svelte.dev/playground/1...

1/2 Huge new feature! But this definitely need more examples and clarification. For instance, it's not clear where the transformation/validation should be (it seems it can be in either "set" or "get", no?). It reminds of getters and setters in POJO, but the semantics seem to be different.

Day 9 — warnings and errors emitted by the compiler, or while your app is running, are now accompanied by links to the docs. Over time, we'll flesh out these docs with more details about what caused the error in question 🎁 demo svelte.dev/playground/8...