# Inherited Component Attributes

A sub component that extends a super component inherits the attributes of the super component.

Attribute values are identical at any level of extension. There is an exception to this rule for the `body` attribute, which we'll look at more closely soon.

Let's start with a simple example. `c:super` has a `description` attribute with a value of "Default description",

```nolang
<!--c:super-->
<aura:component extensible="true">
    <aura:attribute name="description" type="String" default="Default description" />

    <p>super.cmp description: {!v.description}</p>

    {!v.body}
</aura:component>
```

Don’t worry about the `{!v.body}` expression for now. We’ll explain that when we talk about the `body` attribute.

`c:sub` extends `c:super` by setting `extends="c:super"` in its `<aura:component>` tag.

```nolang
<!--c:sub-->
<aura:component extends="c:super">
    <p>sub.cmp description: {!v.description}</p>
</aura:component

```

Note that sub.cmp has access to the inherited `description` attribute and it has the same value in sub.cmp and super.cmp.

Use `<aura:set>` in the markup of a sub component to set the value of an inherited attribute.

## Inherited `body` Attribute

Every component inherits the `body` attribute from `<aura:component>`. The inheritance behavior of `body` is different than other attributes. It can have different values at each level of component extension to enable different output from each component in the inheritance chain. This will be clearer when we look at an example.

Any free markup that is not enclosed in another tag is assumed to be part of the `body`. It's equivalent to wrapping that free markup inside `<aura:set attribute="body">`.

The default renderer for a component iterates through its `body` attribute, renders everything, and passes the rendered data to its super component. The super component can output the data passed to it by including `{!v.body}` in its markup. If there is no super component, you've hit the root component and the data is inserted into `document.body`.

Let's look at a simple example to understand how the `body` attribute behaves at different levels of component extension. We have three components.

c:superBody is the super component. It inherently extends `<aura:component>`.

```nolang
<!--c:superBody-->
<aura:component extensible="true">
    Parent body: {!v.body}
</aura:component>

```

At this point, c:superBody doesn’t output anything for `{!v.body}` as it’s just a placeholder for data that will be passed in by a component that extends c:superBody.

c:subBody extends c:superBody by setting `extends="c:superBody"` in its `<aura:component>` tag.

```nolang
<!--c:subBody-->
<aura:component extends="c:superBody">
    Child body: {!v.body}
</aura:component>

```

`c:subBody` outputs:

```nolang
Parent body: Child body: 
```

In other words, `c:subBody` sets the value for `{!v.body}` in its super component, `c:superBody`.

`c:containerBody` contains a reference to `c:subBody`.

```nolang
<!--c:containerBody-->
<aura:component>
    <c:subBody>
        Body value
    </c:subBody>
</aura:component>

```

In `c:containerBody`, we set the `body` attribute of `c:subBody` to `Body value`. `c:containerBody` outputs:

```nolang
Parent body: Child body: Body value 
```

**See Also**

- [aura:set](/docs/platform/aura-platform/guide/ref-set-intro.md)
- [Component Body](/docs/platform/aura-platform/guide/components-body.md)
- [Component Markup](/docs/platform/aura-platform/guide/components-markup.md)