Mutations article edits for 3.4

[StephenBarlow]

No description provided.

[rektide]

This will be a huge help to our team, thank you.

[benjamn]

@StephenBarlow As I'm working on this article, I noticed we're using React refs in a slightly strange way. Do you think this kind of change is a good idea, or is it more confusing for folks who don't know about useRef?

diff --git a/docs/source/data/mutations.mdx b/docs/source/data/mutations.mdx
index 9ed27e9b4..25a3e227a 100644
--- a/docs/source/data/mutations.mdx
+++ b/docs/source/data/mutations.mdx
@@ -73,7 +73,7 @@ Next, we'll create a component named `AddTodo` that represents the submission fo
 
 ```jsx{3,13}:title=add-todo.jsx
 function AddTodo() {
-  let input;
+  const inputRef = useRef();
   const [addTodo, { data, loading, error }] = useMutation(ADD_TODO);
 
   if (loading) return 'Submitting...';
@@ -84,15 +84,12 @@ function AddTodo() {
       <form
         onSubmit={e => {
           e.preventDefault();
+          const input = inputRef.current;
           addTodo({ variables: { text: input.value } });
           input.value = '';
         }}
       >
-        <input
-          ref={node => {
-            input = node;
-          }}
-        />
+        <input ref={inputRef} />
         <button type="submit">Add Todo</button>
       </form>
     </div>

[benjamn]

@StephenBarlow I enabled the Netlify previews for any PR targeting release-3.4, so that's working now, but I'm stuck on getting <MutationOptions/> to rerender with the new (incomplete) onQueryUpdated section. Is there anything special I need to do to regenerate MDX components like <MutationOptions/>?

[benjamn]

@StephenBarlow This last sentence seems a bit misleading: onQueryUpdated by itself is never the cause of a query being refetched, but merely a way of intercepting/filtering queries that were affected by the mutation's update function or included in the refetchQueries array. I don't think this confusion spills over into other parts of this documentation, so I believe this sentence can be reworded in place.

If that's not enough information to figure out the right wording, I'm happy (as always) to answer questions, but you might also want to read through the Refetch recipes section that I just added, to get a feeling for the relationship between the different client.refetchQueries options.

[benjamn]

Content looks complete to me, though I'm sure there are some formatting tweaks (especially for the tables I added) that we can continue iterating on (either here or in follow-up PRs). Thanks @StephenBarlow!

[benjamn]

Interesting (re: that Netlify build failure)… broken links don't show up for the commit that breaks them, but in the following commit (I think). I'll push a fix momentarily.