# isConcrete()

Returns `true` if the component is concrete, or `false` otherwise. A concrete component is a sub-component in an inheritance chain.

## Signature

`isConcrete()`

## Returns

**Type: `Boolean`** Returns `true` if the component is concrete, or `false` otherwise.

**See Also**

- [getConcreteComponent()](/docs/platform/aura-platform/guide/ref-jsapi-component-getconcretecomponent.md)
- [Favor Composition Over Inheritance](/docs/platform/aura-platform/guide/oo-favor-composition.md)