Merge pull request #8979 from marmelab/FormDataConsumer-getSource

[Doc] Better explain the type of `getSource` and `scopedFormData` in `<FormDataConsumer>`

Author: fzaninotto

docs/Inputs.md

@@ -542,6 +542,8 @@ const PostEdit = () => (
 );
 ```
 
+**Tip:** TypeScript users will notice that `scopedFormData` and `getSource` are typed as optional parameters. This is because the `<FormDataConsumer>` component can be used outside of an `<ArrayInput>` and in that case, these parameters will be `undefined`. If you are inside an `<ArrayInput>`, you can safely assume that these parameters will be defined.
+
 ## Hiding Inputs Based On Other Inputs
 
 You may want to display or hide inputs based on the value of another input - for instance, show an `email` input only if the `hasEmail` boolean input has been ticked to `true`.

docs/SimpleFormIterator.md

@@ -153,6 +153,8 @@ const PostEdit = () => (
 );
 ```
 
+**Tip:** TypeScript users will notice that `scopedFormData` and `getSource` are typed as optional parameters. This is because the `<FormDataConsumer>` component can be used outside of a `<SimpleFormIterator>` and in that case, these parameters will be `undefined`. If you are inside a `<SimpleFormIterator>`, you can safely assume that these parameters will be defined.
+
 **Note**: `<SimpleFormIterator>` only accepts `Input` components as children. If you want to use some `Fields` instead, you have to use a `<FormDataConsumer>`, as follows:
 
 ```jsx