Expose actionData inside the meta function

[kenneth-gray]

Feature request

Would it be possible to run the meta function with the data coming back from the action as well as the loader?

The API for meta could look like this:

function meta({ loaderData, actionData }) {
  ...
}

in place of

function meta({ data }) {
  ...
}

Why?

I'd like to be able to change the document title of a page based on what is being returned by the action. In my particular case I'd like to prefix the title with Error: when there are validation errors on the page. Useful for accessibility when JS fails to load (or is explicitly disabled) for screen readers, because it's the first thing that is announced on page load.

I can work around the JS only version for now by using document.title = `Error: ${document.title}` (being careful to check that this hasn't already been done), but this wouldn't work for the non-JS experience.

Example

function meta({ actionData }) {
  const inputErrors = actionData?.inputErrors ?? [];

  return { title: `${inputErrors.length === 0 ? '' : 'Error: '}Login` };
}

[kenneth-gray]

Raised a simpler change (just adding actionData; no renaming of data) in the following PR: #3534

Things to consider (copied from PR):

• data => loaderData, but that would be a breaking change to the API.
• If data is renamed to loaderData, should parentsData be renamed to parentsLoaderData?
• I started to wonder if the cookie header should also be made available (if it's not http only), so that if your strategy is to use session cookies for error messaging then you'd be able to access that too.