> For the complete documentation index, see [llms.txt](https://docs.ecwid.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ecwid.com/site-themes/develop-site-themes/sections/client.md).

# Client

The `client.ts` file is the client-side entry point for your section. It handles **hydration** — taking the server-rendered HTML and making it interactive in the browser by attaching Vue's reactivity system and event listeners.

### How It Works <a href="#how-it-works" id="how-it-works"></a>

When a page loads, the server-rendered HTML is displayed immediately. The client entry point then:

1. Initializes a Vue app instance with your section component
2. Mounts it onto the existing server-rendered DOM (hydration)
3. Handles live updates when merchants edit content/design in the Editor
4. Unmounts cleanly when the section is removed

### Usage <a href="#usage" id="usage"></a>

```typescript
// client.ts
import { createVueClientApp } from '@lightspeed/crane-api';
import Section from './Section.vue';
import type { Content, Design } from './type';

export default createVueClientApp<Content, Design>(Section);
```

The generic parameters `<Content, Design>` provide type safety for the state passed during mount and update cycles.

### Extensions <a href="#extensions" id="extensions"></a>

`createVueClientApp` accepts an optional second argument for hooking into the app lifecycle:

```typescript
createVueClientApp<Content, Design>(Section, {
  init(app) {
    // Called after the Vue app is created, before mounting.
    // Use this to register plugins, directives, or global components.
  },
  mount(app, rootContainer, state) {
    // Called just before the app mounts to the DOM.
    // Access the initial state (context, content, design data).
  },
  update(app, state) {
    // Called when content or design data changes (e.g., merchant edits in the Editor).
  },
  unmount(app) {
    // Called before the app is unmounted.
    // Clean up any resources not managed by Vue.
  },
});
```

All extension callbacks are optional.

{% hint style="info" %}
For most sections, the basic usage without extensions is sufficient. Extensions are useful when you need to register Vue plugins, set up third-party libraries, or manage resources outside Vue's lifecycle.
{% endhint %}


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