A script to be run `prebuild` to dynamically generate a new vercel.json file with redirects written in Sanity

write-nextjs-redirect.js

const sanityClient = require('@sanity/client')
const fs = require('fs')

const client = sanityClient({
  apiVersion: '2021-04-01',
  dataset: `XXX`,
  projectId: `XXX`,
  useCdn: true,
})

const query = `*[_type == "siteRedirect"][]{from, to}`

client.fetch(query).then((res) => {
  const siteRedirects = res.map(({ from, to }) => ({
    source: from,
    destination: to,
  }))

  const config = {
    trailingSlash: false,
    cleanUrls: true,
    redirects: siteRedirects,
  }

  fs.writeFile(`./vercel.json`, JSON.stringify(config), (err) => {
    if (err) throw err
    console.log(`vercel.json written`)
  })
})