## NavMenu
Menu that provides navigation for your website.
### Top bar
Top bar NavMenu can be used in a variety of scenarios.
:::demo By default Menu is vertical, but you can change it to horizontal by setting the mode prop to 'horizontal'. In addition, you can use the sub-menu component to create a second level menu. Menu provides `background-color`, `text-color` and `active-text-color` to customize the colors.
```html
```
:::
### Side bar
Vertical NavMenu with sub-menus.
:::demo You can use the el-menu-item-group component to create a menu group, and the name of the group is determined by the title prop or a named slot.
```html
Default colors
Custom colors
```
:::
### Collapse
Vertical NavMenu could be collapsed.
:::demo
```html
expand
collapse
```
:::
### Menu Attributes
| Attribute | Description | Type | Accepted Values | Default |
| ------------------- | ---------------------------------------------------------------------------------------------------------- | ------- | --------------------- | -------- |
| mode | menu display mode | string | horizontal / vertical | vertical |
| collapse | whether the menu is collapsed (available only in vertical mode) | boolean | — | false |
| background-color | background color of Menu (hex format) | string | — | #ffffff |
| text-color | text color of Menu (hex format) | string | — | #303133 |
| active-text-color | text color of currently active menu item (hex format) | string | — | #409EFF |
| default-active | index of currently active menu | string | — | — |
| default-openeds | array that contains indexes of currently active sub-menus | Array | — | — |
| unique-opened | whether only one sub-menu can be active | boolean | — | false |
| menu-trigger | how sub-menus are triggered, only works when `mode` is 'horizontal' | string | hover / click | hover |
| router | whether `vue-router` mode is activated. If true, index will be used as 'path' to activate the route action | boolean | — | false |
| collapse-transition | whether to enable the collapse transition | boolean | — | true |
### Menu Methods
| Methods Name | Description | Parameters |
| ------------ | ------------------------- | ------------------------------------- |
| open | open a specific sub-menu | index: index of the sub-menu to open |
| close | close a specific sub-menu | index: index of the sub-menu to close |
### Menu Events
| Event Name | Description | Parameters |
| ---------- | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| select | callback function when menu is activated | index: index of activated menu, indexPath: index path of activated menu, item: the selected menu item, routeResult: result returned by `vue-router` if `router` is enabled |
| open | callback function when sub-menu expands | index: index of expanded sub-menu, indexPath: index path of expanded sub-menu |
| close | callback function when sub-menu collapses | index: index of collapsed sub-menu, indexPath: index path of collapsed sub-menu |
### Menu-Item Events
| Event Name | Description | Parameters |
| ---------- | ------------------------------------------- | ---------------------- |
| click | callback function when menu-item is clicked | el: menu-item instance |
### SubMenu Attributes
| Attribute | Description | Type | Accepted Values | Default |
| --------------------- | ---------------------------------------------------------------------------------------------------------------- | ------- | --------------- | ----------------------------------------------- |
| index | unique identification | string | — | — |
| popper-class | custom class name for the popup menu | string | — | — |
| show-timeout | timeout before showing a sub-menu | number | — | 300 |
| hide-timeout | timeout before hiding a sub-menu | number | — | 300 |
| disabled | whether the sub-menu is disabled | boolean | — | false |
| popper-append-to-body | whether to append the popup menu to body. If the positioning of the menu is wrong, you can try setting this prop | boolean | - | level one SubMenu: true / other SubMenus: false |
### Menu-Item Attributes
| Attribute | Description | Type | Accepted Values | Default |
| --------- | --------------------- | ----------- | --------------- | ------- |
| index | unique identification | string/null | — | null |
| route | Vue Router object | object | — | — |
| disabled | whether disabled | boolean | — | false |
### Menu-Item-Group Attributes
| Attribute | Description | Type | Accepted Values | Default |
| --------- | ----------- | ------ | --------------- | ------- |
| title | group title | string | — | — |