Fixes#4880.
Fixes#6737.
This will be a breaking change for anyone who uses the StartStopNotifier
type in their / implements custom stores.
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Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
This is an overhaul of custom elements in Svelte. Instead of compiling to a custom element class, the Svelte component class is mostly preserved as-is. Instead a wrapper is introduced which wraps a Svelte component constructor and returns a HTML element constructor. This has a couple of advantages:
- component can be used both as a custom element as well as a regular component. This allows creating one wrapper custom element and using regular Svelte components inside. Fixes#3594, fixes#3128, fixes#4274, fixes#5486, fixes#3422, fixes#2969, helps with https://github.com/sveltejs/kit/issues/4502
- all components are compiled with injected styles (inlined through Javascript), fixes#4274
- the wrapper instantiates the component in `connectedCallback` and disconnects it in `disconnectedCallback` (but only after one tick, because this could be a element move). Mount/destroy works as expected inside, fixes#5989, fixes#8191
- the wrapper forwards `addEventListener` calls to `component.$on`, which allows to listen to custom events, fixes#3119, closes#4142
- some things are hard to auto-configure, like attribute hyphen preferences or whether or not setting a property should reflect back to the attribute. This is why `<svelte:options customElement={..}>` can also take an object to modify such aspects. This option allows to specify whether setting a prop should be reflected back to the attribute (default `false`), what to use when converting the property to the attribute value and vice versa (through `type`, default `String`, or when `export let prop = false` then `Boolean`), and what the corresponding attribute for the property is (`attribute`, default lowercased prop name). These options are heavily inspired by lit: https://lit.dev/docs/components/properties. Closes#7638, fixes#5705
- adds a `shadowdom` option to control whether or not encapsulate the custom element. Closes#4330, closes#1748
Breaking changes:
- Wrapped Svelte component now stays as a regular Svelte component (invokeing it like before with `new Component({ target: ..})` won't create a custom element). Its custom element constructor is now a static property named `element` on the class (`Component.element`) and should be regularly invoked through setting it in the html.
- The timing of mount/destroy/update is different. Mount/destroy/updating a prop all happen after a tick, so `shadowRoot.innerHTML` won't immediately reflect the change (Lit does this too). If you rely on it, you need to await a promise
Closes#3310
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Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Closes#6050
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Co-authored-by: Bob Fanger <b.fanger@wearetriple.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>
Closes#5085
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Co-authored-by: Marcin Wicha <23581770+marcin-wicha@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Closes#7771
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Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>
Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>
* important modifier for style directive
* docs
* Exclude third param if false
third param for set_style is optional
* Remove unused test
Runtime test doesn't work because of weird behaviour of computed style
the puppeteer test should cover it
* remove unnecessary test
Co-authored-by: tanhauhau <lhtan93@gmail.com>
* Add clarification on how reactivity works
Based on the fact that there are multiple issues were opened related to a perceived bug on the reactive variables, I thought it would be good to add a clarification on the docs. Part of the text is taken from [this comment](https://github.com/sveltejs/svelte/issues/7818#issuecomment-1230374639) that I found super useful.
* Reword based on PR comments
Simon Holthausen
Robin Munn
Simon H
Cas
abirtley
xxkl1
James Scott-Brown
Nguyen Tran
Dave Lunny
Henrik Giesel
Bob Fanger
Brandon McConnell
Brad Dougherty
Tan Li Hau
Theodor Steiner
Yuichiro Yamashita
Alvin Ramskogler
Maxime Dupont
Alicia Sykes
Kyrre Gjerstad
Satvik
wackbyte
Geoff Rich
Nilesh
Ben McCann
Pat Cavit
Maximiliano Ruani
Josiah Nieves
gtmnayan
Don Alfons
metonym
Marcos Mercuri
Shawn
MCMXC
tanhauhau