Svelte 5 Event Handlers Should Error on Invalid Case In Typescript. about svelte HOT 5 CLOSED

Technically, an event with whatever name can be dispatched on any element, so any on* handler must be allowed.
I see your point, and likely it could be more useful as an eslint rule.

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My suggestion would be to catch it in the typings. I know most attributes are case insensitive. But these events are used by svelte and do not work with any casing

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This is handled by typings already. Furthermore we can't know what custom events with weird typing someone might listen to. Enhancing the types for that in user land is a known pattern, if this was a warning inside the compiler we would need more options to silence it. Therefore closing

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The casing is not handling by typings. Right now any casing is valid to the types but only full lowercase is valid to svelte. It seems like svelte should either work with any case or warn on invalid casing.

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Oh right, language tools lowercases them - we need to stop doing that for event attributes in Svelte 5. Opened sveltejs/language-tools#2345 for that

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