@appsemble/preact

Appsemble Preact SDK

Build your own blocks using Preact

Table of Contents

• Installation
• Usage
  • bootstrap()
  • useBlock()
  • <FormattedMessage />
• License

Installation

npm install @appsemble/preact preact

Usage

This package integrates Preact with @appsemble/sdk. Please read the documentation for a better understanding of how to use it.

bootstrap()

The bootstrap function takes a Preact component as an argument and renders. It takes the Appsemble block context as its props, extended with the ready() function. The ready() function needs to be called when the block is done rendering. Actions won’t be finalized for any blocks on the page, until all blocks are ready.

import { bootstrap } from '@appsemble/preact';
import { useEffect } from 'preact/hooks';

bootstrap(({ actions }) => {
  useEffect(() => {
    ready();
  }, []);

  return (
    <button onClick={() => actions.onClick()} type="button">
      Hello world!
    </button>
  );
});

Note: The script will be loaded only once. The component is then bootstrapped for every instance of your block type that is loaded by the app creator.

useBlock()

Get the block context. This is available for components that are rendered within a subtree of a component rendered by bootstrap

import { useBlock } from '@appsemble/preact';
import { type VNode } from 'preact';

export function MyButton(): VNode {
  const { actions } = useBlock();

  return (
    <button onClick={() => actions.onClick()} type="button">
      Hello world!
    </button>
  );
}

<FormattedMessage />

This helper component renders a translated message ID.

import { FormattedMessage } from '@appsemble/preact';
import { type VNode } from 'preact';

interface MyButtonProps {
  readonly name: string;
}

export function MyButton({ name }: MyButtonProps): VNode {
  return (
    <button type="button">
      <FormattedMessage id="myButtonLabel" values={{ name }} />
    </button>
  );
}

License

LGPL-3.0-only © Appsemble

Changelog

[0.29.8] - 2024-08-08

Added

• Block(form): Use the accept requirement of input fields to show an icon in the upload button.
• Block(list): Show the filename and filetype icon in the header of list items, with a header value remapping to an asset id.
• App: Unregister service worker in app debug page.
• Server: Add Access-Control-Expose-Headers: 'Content-Disposition' header to getAssetById endpoint.
• Utils: Add assets content type and content disposition utils.
• Utils: Add functions for mime type operations and icons.

Changed

• Block(form): Show the upload button to the right in repeated file inputs.
• Block(form): Use the mime type of files in the file input to show a placeholder.
• App: Make debug page path case insensitive.

Fixed

• Block(form): Don't show the message for long submission if there are form errors.
• Server: Allow patching resources with assets by name.