:: BASE_DOC ::

## API

### BackTop Props

name | type | default | description | required
-- | -- | -- | -- | --
external-classes | Array | - | `['t-class', 't-class-icon', 't-class-text']` | N
fixed | Boolean | true | \- | N
icon | String / Boolean / Object / Slot | - | \- | N
text | String | '' | \- | N
theme | String | round | options：round/half-round/round-dark/half-round-dark | N

### BackTop Events

name | params | description
-- | -- | --
to-top | \- | \-
