# Create app.

App is the entry for an app.

```typescript
import { App } from '@vert/core'
import RootComponent from './layout/default.vue'

const app = new App({
  element: '#my-app',
  RootComponent
})

app.start()
```

If you want to destroy it:

```typescript
app.destroy()
```

## API

```typescript
/**
 * App is the basic unit for a project.
 *
 * @class App
 */
class App {
  /**
   * Register target as a singleton provider in global.
   *
   * @static
   * @template T
   * @param {TConstructor[]} Providers
   */
  static addSingleton (...Providers: TConstructor[]): typeof App

  /**
   * Register target as a transient provider in global.
   *
   * @static
   * @template T
   * @param {TConstructor[]} Providers
   */
  static addTransient (...Providers: TConstructor[]): typeof App

  /**
   * Name of this app instance.
   *
   * @type {string}
   * @readonly
   * @memberof App
   */
  get name (): string

  /**
   * Vue store object of this app,
   *
   * @type {*}
   * @readonly
   * @memberof App
   */
  get store (): any

  /**
   * View model of this app,
   *
   * @type {Vue}
   * @readonly
   * @memberof App
   */
  get viewModel (): Vue

  /**
   * Root component constructor.
   *
   * @readonly
   * @type {TRootComponent}
   * @memberof App
   */
  get RootComponent (): TRootComponent

  /**
   * Start up this app.
   *
   * @memberof App
   */
  start (): void

  constructor (option: IAppOption)
}

/**
 * Constructor param of AppPage.
 *
 * @interface IAppPage
 */
interface IAppOption {
  /**
   * HTML element to mount.
   *
   * @type {(string | HTMLElement)}
   * @memberof IAppOption
   */
  element?: string | HTMLElement

  /**
   * You can specify a name for this app instance.
   *
   * @type {string}
   * @memberof IAppOption
   */
  name?: string

  /**
   * Root component the root vue component.
   *
   * @type {TRootComponent}
   * @memberof IAppOption
   */
  RootComponent: TRootComponent

  /**
   * Vue router instance for this app.
   *
   * @type {*}
   * @memberof IAppOption
   */
  router?: any

  /**
   * Vuex instance for this app.
   *
   * @type {*}
   * @memberof IAppOption
   */
  store?: any

  /**
   * Created hook.
   *
   * @type {THookFunction}
   * @memberof IAppOption
   */
  created?: THookFunction

  /**
   * Mounted hook.
   *
   * @type {THookFunction}
   * @memberof IAppOption
   */
  mounted?: THookFunction

  /**
   * Before destroy hook.
   *
   * @type {THookFunction}
   * @memberof IAppOption
   */
  beforeDestroy?: THookFunction
}
```