Mesa guide / Template syntax

{#await}

Render a promise's three states: pending, resolved and rejected.

<script>
  const load = () => fetch('/api/user').then((r) => r.json())
</script>

{#await load()}
  <p>Loading...</p>
{:then user}
  <p>Hello {user.name}</p>
{:catch error}
  <p>Failed: {error.message}</p>
{/await}

{:then} and {:catch} are optional, the pending part can be empty, and {:then} can omit the name when you do not need the value.

One block form only

Write the whole {#await p}...{:then v}...{/await} block. The one-line {#await p then v} form is a compile error.

For more than a render

{#await} is for showing a promise in the template. For loading data, caching and cancelling, see Async.

Spec: VISION.md § 9.3