Visual editing for SvelteKit, on WordPress.

1. 01

   Allow the editor to display your site

   Copy this into src/hooks.server.ts.

   import type { Handle } from '@sveltejs/kit';
   
   export const handle: Handle = async ({ event, resolve }) => {
     const response = await resolve(event);
     response.headers.set('Content-Security-Policy', "frame-ancestors 'self' https://cms.example.com");
     return response;
   };

   Prerendered pages are served as static files: set the same header on your host.

2. 02

   Add the bridge

   Install the package, then load the bridge from the root layout.

   npm install leiho

   <script>
     import { onMount } from 'svelte';
   
     let { children } = $props();
   
     onMount(() => {
       if (window.self === window.top) return;
       import('leiho').then(({ initLeihoBridge }) => {
         // Already on screen: don't hide the page.
         initLeihoBridge({ wpOrigin: 'https://cms.example.com', cloakTimeout: 0 });
       });
     });
   </script>
   
   {@render children()}

3. 03

   Read the content

   Load each page in +page.server.ts.

   import { error } from '@sveltejs/kit';
   import { loadLeihoContent, indexLeihoContent } from 'leiho/content';
   
   export async function load({ url }) {
     const { data } = await loadLeihoContent({ url: 'https://cms.example.com/wp-json/leiho/v1/export' });
     const page = indexLeihoContent(data).byPath(url.pathname);
     if (!page) error(404, 'Not found');
     return { page };
   }

   Serverless host with a read-only disk? Pass snapshot: false to loadLeihoContent.

4. 04

   Mark what editors can change

   Spread field() on each element editors should change. Always render the element, even when its value is empty.

   <script>
     import { field, entry } from 'leiho';
     // field() writes data-wp-post + data-wp-field, entry() names a section.
   // Flexible content rows: block(page, 'sections', i, 'Label').
     let { page } = $props();
   </script>
   
   <section {...entry(page, 'Hero')}>
     <h1 {...field(page, 'hero_title')}>{page.fields.hero_title}</h1>
     <img {...field(page, 'hero_image')} src={page.fields.hero_image?.url} alt={page.fields.hero_image?.alt} />
     {#each page.fields.cards ?? [] as card, i}
       <article {...field(page, `cards.${i}.title`)}>{card.title}</article>
     {/each}
   </section>

Replace https://cms.example.com with your WordPress address. In wp-admin, Leiho → Get started shows these steps with your address filled in, checks each one, and can give the whole setup to your coding agent as one prompt.