Merge pull request #404 from cloojure/patch-4

small correction
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Juho Teperi 2018-11-05 11:40:55 +02:00 committed by GitHub
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@ -30,11 +30,11 @@ We'll start with a code fragment, because it is worth a 1000 words:
Notes: Notes:
1. This example uses a Form-2 component, which allows us to retain state outside of the renderer `fn`. The same technique would work with a Form-3 component. 1. This example uses a Form-2 component, which allows us to retain state outside of the renderer `fn`. The same technique would work with a Form-3 component.
2. We capture state in `!video`. In this example, the state we capture is a reference to a [video HTML element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/video). 2. We capture state in `!video`. In this example, the state we capture is a reference to a [video HTML element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/video).
2. `!video` is a `clojure.core/atom` and not a `reaagent.core/atom`. We don't use a normal atom because refs never change during the lifecycle of a component and if we used a reagent atom, it would cause an unnecessary re-render when the ref callback mutates the atom. 3. `!video` is a `clojure.core/atom` and not a `reaagent.core/atom`. We use a normal Clojure `atom` because refs never change during the lifecycle of a component and if we used a reagent atom, it would cause an unnecessary re-render when the ref callback mutates the atom.
4. On the `:video` component there's a `:ref` callback function which establishes the state in `!video`. You can attach a ref callback to any of the Hiccup elements. 4. On the `:video` component there's a `:ref` callback function which establishes the state in `!video`. You can attach a ref callback to any of the Hiccup elements.
5. Thereafter, `@!video` is used with the `:button's` `:on-click` to manipulate the `video` DOM methods. 5. Thereafter, `@!video` is used with the `:button's` `:on-click` to manipulate the `video` DOM methods.
5. For full notes [read Paulus' blog post](https://presumably.de/reagent-mysteries-part-3-manipulating-the-dom.html) 6. For full notes [read Paulus' blog post](https://presumably.de/reagent-mysteries-part-3-manipulating-the-dom.html)
6. For more background on callback refs, see [React's documentation](https://facebook.github.io/react/docs/more-about-refs.html) 7. For more background on callback refs, see [React's documentation](https://facebook.github.io/react/docs/more-about-refs.html)
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