Svelte: Redirect to new page ID

Suppose

  • that your website has page IDs in the sense of domain.com/PAGEID/slug. For example, you're probably seeing this very page at the address edstrom.dev/csbxq/redirect-to-new-page-ids-in-sveltekit, so the ID is csbxq.
  • that you update the ID to use new algorithm, so now it's going to be 6uXpfOI2c9fJdh2aa22. Time to set up a redirect!

I'll assume your page's loader (the file you've got on a path like src/routes/[id]/[[slug]]/+page.js) contains this: 

import { error } from '$sveltejs/kit'
import posts from '$lib/posts.json'

export function load({ params }) {
    let post = posts[params.id]
    if (post) return post
    
    error(404, "Not found")
}

Edit that to something like this. 

import { error, redirect } from '$sveltejs/kit'
import posts from '$lib/posts.json'
import v1_to_v2 from '$lib/v1_to_v2.json' // assumed a table of old and new ID

export function load({ params }) {
  let post = posts[params.id]
  if (post) return post

  // Redirect from v1 to v2 id
  let idv2 = v1_to_v2[params.id]
  if (idv2) redirect(308, `/${idv2}`)
  
  error(404, "Not found")
}

This assumes that navigating to just domain.com/IDV2 is satisfactory.

To also include the slug in the redirection (remember the slug in domain.com/PAGEID/slug?), I'll assume your post object contains metadata post.id and post.slug and then we can do the redirection like this: 

// ...
export function load({ params }) {
  let post = posts[params.id]
  if (post) return post

  // Redirect from v1 to v2 id
  post = posts[v1_to_v2[params.id]]
  if (post) redirect(308, `/${post.id}/${post.slug}`)

  error(404, "Not found")
}
Created (2 months ago)