> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nanoforge.eu/llms.txt
> Use this file to discover all available pages before exploring further.

# COMPONENT_SYSTEM_LIBRARY variable

> Registration symbol for the component-system (ECS) library slot.

import { PageLink } from '/snippets/tsdocs/PageLink.jsx';
import { RefLink } from '/snippets/tsdocs/RefLink.jsx';

# COMPONENT\_SYSTEM\_LIBRARY

## Summary

Registration symbol for the component-system (ECS) library slot.

## Signature

```typescript theme={null}
COMPONENT_SYSTEM_LIBRARY: unique symbol
```

## Remarks

Pass this symbol to `NanoforgeApplication.use` when registering a custom component-system library, or use the shorthand `NanoforgeApplication.useComponentSystem`.