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Update ComponentNotRerendering.md

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Juho Teperi 2019-01-03 20:49:33 +02:00 committed by GitHub
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doc/FAQ/ComponentNotRerendering.md
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@ -14,10 +14,11 @@ We'll deal with these two cases seperately.
If a ratom changes but your Component doesn't update, then the gotchas to look out for are:
1. Make sure you are using a `reagent.core/atom` (i.e. a Reagent ratom) instead of a normal `clojure.core/atom`. Carefully check the `require` at the top of the `ns`. Components are only reactive with respect to Reagent ratoms. They don't react to changes in a Clojure atom.
2. Make sure you actually `deref` your ratom (e.g, @app-state) during the render function of your component. It is a common mistake for people to forget the leading `@`. Note that derefs that happen outside of the render function (such as during event handlers) do not make your component reactive to that ratom.
3a. Make sure your ratom will survive a rerender. Either declare it as a global var, or use a form-2 or form-3 component. [Read this](https://github.com/reagent-project/reagent-cookbook/tree/master/basics/component-level-state) if you want to understand why.
3b. If you put your ratom in a form-2 or form-3 component, be sure you are calling that function using \[square brackets\], not \(parenthesis\).
4. Make sure to `deref` your ratom outside of a seq or wrap that seq in a `doall`. See this [related issue](https://github.com/reagent-project/reagent/issues/18).
2. Make sure you actually `deref` your ratom (e.g. `@app-state`) during the render function of your component. It is a common mistake for people to forget the leading `@`. Note that derefs that happen outside of the render function (such as during event handlers) do not make your component reactive to that ratom.
3. Make sure your ratom will survive a rerender. Either declare it as a global var, or use a form-2 or form-3 component. [Read this](https://github.com/reagent-project/reagent-cookbook/tree/master/basics/component-level-state) if you want to understand why.
4. If you put your ratom in a form-2 or form-3 component, be sure you are calling that function using `[square brackets]`, not `(parenthesis)`.
When function (component) is called using `( )` Reagent doesn't create new component, but instead just places the function's return value into current component. In this case the function closure which should hold the local state doesn't work.
5. Make sure to `deref` your ratom outside of a seq or wrap that seq in a `doall`. See this [related issue](https://github.com/reagent-project/reagent/issues/18).
### Props Change