aura:component

The root of the component hierarchy. Provides a default rendering implementation.

Components are the functional units of Aura, which encapsulate modular and reusable sections of UI. They can contain other components or HTML markup. The public parts of a component are its attributes and events. Aura provides out-of-the-box components in the aura and ui namespaces.

Every component is part of a namespace. For example, the button component is saved as button.cmp in the ui namespace can be referenced in another component with the syntax <ui:button label="Submit"/>, where label="Submit" is an attribute setting.

To create a component, follow this syntax.

1<aura:component>
2    <!-- Optional coponent attributes here -->
3    <!-- Optional HTML markup -->
4    <div class="container"> 
5        Hello world!
6        <!-- Other components -->
7    </div>
8</aura:component>

A component has the following optional attributes.

Attribute	Type	Description
`access`	String	Indicates whether the component can be used outside of its own namespace. Possible values are `public` (default), and `global`.
`controller`	String	The server-side controller class for the component. The format is `namespace.myController`.
`description`	String	A description of the component.
`extends`	Component	The component to be extended.
`extensible`	Boolean	Set to `true` if the component can be extended. The default is `false`.
`implements`	String	A comma-separated list of interfaces that the component implements.
`isTemplate`	Boolean	Set to `true` if the component is a template. The default is `false`. A template must have `isTemplate="true"` set in its `<aura:component>` tag. `1<aura:component isTemplate="true" extends="aura:template">`
`template`	Component	The template for this component. A template bootstraps loading of the framework and app. The default template is `aura:template`. You can customize the template by creating your own component that extends the default template. For example: `<aura:component extends="aura:template" ... >`

aura:component includes a body attribute defined in a <aura:attribute> tag. Attributes usually control the output or behavior of a component, but not the configuration information in system attributes.

Attribute	Type	Description
`body`	`Component[]`	The body of the component. In markup, this is everything in the body of the tag.

Lightning Components Developer Guide

aura:component