Fresh archive: Loading fallback — deco developer docs

Documentação de produto descontinuado — Fresh e o antigo admin foram descontinuados. Estas instruções são mantidas para migração e referência histórica. Novos projetos usam Blocks 7.x e o Editor de Sites do Studio.

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Retired Fresh / Deno reference. This original guide preserves the earlier runtime APIs, Preact/HTMX examples, and any former admin steps. Use it when maintaining that runtime; consult the Studio Site Editor guides for current editing. Migration notes distinguish editor and framework migration.

Loading Fallback

Overview

Loading fallbacks are a powerful concept available to be used since 1.54.0 version, to handle loading state of sections using data from third party APIs. They allow you to gracefully handle loading states and prevent the entire application from hanging due to some third party API

In deco, creating a loading fallback is as simple as exporting a component function named LoadingFallback.

The pre-requisites to make your component work is having the following dependencies in versions higher or equal than below:

{
  "imports": {
    "deco/": "https://denopkg.com/deco-cx/deco@1.54.0/",
    "$fresh/": "https://denopkg.com/deco-cx/fresh@1.3.2/",
    "preact": "https://esm.sh/preact@10.16.0",
    "preact/": "https://esm.sh/preact@10.16.0/",
    "preact-render-to-string": "https://esm.sh/*preact-render-to-string@6.2.0",
    "@preact/signals": "https://esm.sh/*@preact/signals@1.1.3",
    "@preact/signals-core": "https://esm.sh/@preact/signals-core@1.3.0"
  }
}

Example: Creating a Loading Fallback

To create a loading fallback, you can follow these steps:

Pick your selected Section (e.g ProductShelf.tsx)
Export a function named LoadingFallback.

// ProductShelf.tsx
export interface Props {
    myProp: string;
}
 
export function LoadingFallback() {
  // Renderer spinners, skeletons and other placeholder
  return (
    <div>
      <h2>loading...</h2>
    </div>
  );
}
 
export default function ProductShelf(props: Props) {
    ...
}

If ProductShelf uses a data coming from a slow third party API, the LoadingFallback component will be rendered instead. If no loading fallback is set, a default fallback will be rendered instead