How do I trigger SvelteKit to rerender a specific field

July 4, 2023

I have a document object containing fields like title and name.

When an operation fails, I’m updating the document special field _failures with the error messages, for example I update

doc._failures.title = {failCode: 404, error: 'document unavailable'}

Now in sveltekit, when I display the fields, I check if there’s not a corresponding error in doc._failures.

My problem is that when I update _failures, Sveltekit doesn’t ‘realize’ I added fields into it, and never renders the failure messages.

I have a component tree I’m providing the root of with doc, but I’d like only nested fields to refresh if there’s a failure associated to them. For example doc.contact.email.personal

Any suggestions?

NOTE:
Just if you wonder how my code adds the _failure here’s a snippet:

if (result.type === 'failure') {
    const error = JSON.parse(result.data).error;
    console.log("Adding _failure to ", accessor)
    _set(doc, '_failures.'+accessor, { failCode:result.status, error } )
}

>Solution :

Reactivity is based on assignments, _set is not an assignment.

You could add doc = doc afterwards to invalidate doc. This will cause any UI to update that uses doc reactively (i.e. if the reactivity chain is not broken that should be enough).