:title
COMPONENT

:sig
COMPONENT(Request& context)

:see
>component
>component_render
>1_RENDER
>1_INIT
>1_ONCE
>1_WS

:content
Defines the default component entrypoint for the current `.uce` file.

`component()` and `component_render()` call `COMPONENT(Request& context)` by default. Named component entrypoints use `COMPONENT:NAME(Request& context)`.

If the same file defines `ONCE(Request& context)`, that hook runs once per request before the first `COMPONENT()` or `COMPONENT:NAME()` call for that unit.

If the file defines `INIT(Request& context)`, that hook runs once when the worker loads the compiled unit into memory.

## Why It Exists

This keeps page rendering and component rendering separate:

- direct HTTP requests call `RENDER(Request& context)`
- WebSocket messages call `WS(Request& context)`
- component helpers call `COMPONENT(Request& context)` or `COMPONENT:NAME(Request& context)`

A file intended only for component reuse can define `COMPONENT()` without defining `RENDER()`.

Inside component handlers, props arrive through `context.props`.

When you call `component(":NAME", props, context)` or `component_render(":NAME", props, context)`, the runtime resolves `:NAME` against the current `.uce` file instead of requiring the file name again.

## Example

```cpp
COMPONENT(Request& context)
{
    <><section><?: component(":BODY", context.props, context) ?></section></>
}

COMPONENT:BODY(Request& context)
{
    <><p><?= context.props["body"] ?></p></>
}
```

## Related Concepts

- PHP: view partials, reusable include files, small template helpers, and server-side component-like rendering patterns
- JavaScript / Node.js: reusable component functions, React or Vue components, and server-rendered partials