Production Preview: default async resolveProductionUrl export

[kroneman]

Is your feature request related to a problem? Please describe.

https://www.sanity.io/docs/preview-content-on-site

When using production preview, I would like to be able to configure the environment to preview by leveraging a plugin. Something along the lines of.

// ./resolveProductionUrl.js
import client from 'part:@sanity/base/client';

const previewSecret = 'MY_SECRET'
const PREVIEW_QUERY = `*[_type == "preview_environment_storage"] | order(_createdAt desc)`;

export default async function resolveProductionUrl(document) {
  const documentType = document._type;
  const [configuredHost] = await client.fetch(PREVIEW_QUERY);

  return `${configuredHost.url}/api/preview?secret=${previewSecret}&type=${documentType}&slug=${document.slug.current}`
}

where preview_environment_storage gets managed by plugin.

Describe the solution you'd like

Update the calling context of resolveProductionUrl.js to expect a promise that resolves a url.

Describe alternatives you've considered

Storing the environment in local storage instead of as a sanity type. Using an env variable to differentiate between development and production mode

• Env variables work great for a local, prod setup, currently using local, test, prod setup

Additional context

[homerjam]

Alternative suggestion: make it possible to use env vars, even SANITY_STUDIO_* would be great

[rexxars]

This should now be easier to do in Sanity Studio v3, since the configuration is fully javascript based.