Fetch data from two or more endpoints in SvelteKit

Real quick example of how I used Promise.all to fetch data from multiple endpoints in SvelteKit.

This uses the server side fetch that is part of SvelteKit and is destructured into the load function.

Note that the code is in the <script context="module"> tag, this means it runs before the page is loaded.

<script context="module">
  export async function load({ fetch }) {
    const [pagesReq, postsReq] = await Promise.all([
      fetch('/pages.json'),
      fetch('/posts.json'),
    ])
    if (pagesReq.ok && postsReq.ok) {
      const { pages } = await pagesReq.json()
      const { posts } = await postsReq.json()
      return {
        props: {
          pages,
          posts,
        },
      }
    }
  }
</script>

Full file looks a little like this example:

<!-- src/routes/index.svelte -->
<script context="module">
  export async function load({ fetch }) {
    const [pagesReq, postsReq] = await Promise.all([
      fetch('/pages.json'),
      fetch('/posts.json'),
    ])
    if (pagesReq.ok && postsReq.ok) {
      const { pages } = await pagesReq.json()
      const { posts } = await postsReq.json()
      return {
        props: {
          pages,
          posts,
        },
      }
    }
  }
</script>

<script>
  import PagesList from '$lib/nav.svelte'
  export let pages, posts
</script>

<PagesList {pages} />

<h1>Welcome to SvelteKit</h1>
<p>
  Visit <a href="https://kit.svelte.dev">kit.svelte.dev</a> to read the
  documentation
</p>

{#each posts as { title, slug, excerpt }}
  <a href={`/posts/${slug}`}>
    <p>{title}</p>
    <p>{excerpt}</p>
  </a>
{/each}

That’s it!