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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Attrs are never observed unless added with `@attr` decorator","articleBody":"Hi folks,\r\n\r\nWhile I was testing the attributes — trying to work my way around #207 — I found another subtle detail. Manually initialized attributes are never observed.\r\n\r\nCatalyst's guide provides the following example for vanilla users: https://github.com/github/catalyst/blob/main/docs/_guide/attrs.md#what-about-without-decorators.\r\n\r\nPlease notice the second argument there `defineObservedAttributes(HelloWorldElement, ['foo'])` and compare it with the actual function declaration:\r\n\r\nhttps://github.com/github/catalyst/blob/a8fb3ba59a4ac258d0fe64a50ecd3b6997f5f016/src/attr.ts#L99\r\n\r\nIt doesn't expect the second argument (`arguments` aren't used either).\r\n\r\nNow, internally `defineObservedAttributes()` pulls attribute names from `getAttrNames()`, which, in turn, pulls them from `attrs` (`WeakMap`). The only way to populate `attrs` is to use `@attr` decorator:\r\n\r\nhttps://github.com/github/catalyst/blob/a8fb3ba59a4ac258d0fe64a50ecd3b6997f5f016/src/attr.ts#L15\r\n\r\nMaybe I'm missing something, but it seems like there's no way to specify observed attributes without decorators. In any case, it'd be very nice to clarify that 🙂\r\n\r\nThank you!","author":{"url":"https://github.com/kristoforsalmin","@type":"Person","name":"kristoforsalmin"},"datePublished":"2022-04-29T12:49:01.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/208/catalyst/issues/208"}