---
title: "Surface lifecycle"
description: "useAppContext().lifecycle は一つの surface mount の resource を所有し、unmount または exact runtime identity 変更時に cleanup します。"
url: "https://sotaagents.ai/ja/manual/developer-guide/surface-lifecycle"
generated_by: "sotaagents-ldp"
docs_index: "https://sotaagents.ai/manual/llms.txt"
locale: "ja"
---

# Surface lifecycle

`useAppContext().lifecycle` は一つの surface mount の resource を所有し、unmount または exact runtime identity 変更時に cleanup します。

| API | 用途 |
| --- | --- |
| `signal` | Unmount 時に abort される `AbortSignal`。 |
| `onDispose(dispose)` | App cleanup を登録し unregister function を返します。 |
| `listen(target, type, listener, options?)` | Mount-owned event listener を追加し disposer を返します。 |

TSX

```
import { useEffect, useState } from 'react';
import { useAppContext } from '@sota/platform';

export function OnlineState() {
  const { lifecycle } = useAppContext();
  const [online, setOnline] = useState(navigator.onLine);
  useEffect(() => {
    const update = () => setOnline(navigator.onLine);
    const stopOnline = lifecycle.listen(window, 'online', update);
    const stopOffline = lifecycle.listen(window, 'offline', update);
    return () => {
      stopOnline();
      stopOffline();
    };
  }, [lifecycle]);
  return <p>{online ? 'Online' : 'Offline'}</p>;
}
```

TypeScript

```
import { useEffect } from 'react';
import { useAppContext } from '@sota/platform';

export function MountTimer() {
  const { lifecycle } = useAppContext();
  useEffect(() => {
    const timer = window.setInterval(() => console.log('tick'), 30_000);
    const unregister = lifecycle.onDispose(() => window.clearInterval(timer));
    return () => {
      window.clearInterval(timer);
      unregister();
    };
  }, [lifecycle]);
  return null;
}
```

Process-global listener や timer の代わりにこれらの primitive を使います。React cleanup が disposer を先に呼んでも、surface 消失時には Core が cleanup を保証します。