# Blocks

Our blocks are generally made up of up to 4 files:

```
|- block.js
|- editor.scss
|- index.js
|- style.scss
```

The only required file is `index.js`, this sets up the block using [`registerBlockType`.](https://wordpress.org/gutenberg/handbook/designers-developers/developers/block-api/block-registration/) Each block has edit and save functions.

The scss files are split so that things in `style` are added to the editor _and_ frontend, while styles in `editor` are only added to the editor. Most of our blocks should use core components that won't need CSS though.

### Editing

A simple edit function can live in `index.js`, but most blocks are a little more complicated, so the edit function instead returns a Block component, which lives in `block.js`. By using a component, we can use React lifecycle methods to fetch data or save state.

The [Newest Products block](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/js/blocks/product-new/block.js) is a good example to read over, this is a simple block that fetches the products and renders them using the ProductPreview component.

We include settings in the sidebar, called the Inspector in gutenberg. [See an example of this.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/js/blocks/product-new/block.js#L71)

Other blocks have the concept of an "edit state", like when you need to pick a product in the Featured Product block, or [pick a category in the Products by Category block.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/js/blocks/product-category/block.js#L140)

### Saving

Usually blocks can be converted to HTML in the save function, so that what's saved into the database is the same HTML that's rendered on the frontend. Our blocks are different since they need to show the latest products and reflect any changes to products.

The grid blocks are saved as shortcodes using [`getShortcode`,](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/js/utils/get-shortcode.js) but the Featured Product block is considered a "dynamic block", so we use PHP to build that each time the post is loaded on the frontend. The code for that is set up when [the block is registered in PHP](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/php/class-wgpb-block-library.php#L216), and lives in [`WGPB_Block_Featured_Product`.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/5c9d587fcc0b9e652813a42b66eafa5520c7ac88/assets/php/class-wgpb-block-featured-product.php)