# @antv/event-emitter > event-emitter for @antvis. ## Install > npm i --save @antv/event-emitter ## Usage ```js import EE from '@antv/event-emitter'; const ee = new EE(); ee.on('mouseover', () => {}); ee.once('click', () => {}); ee.on('*', () => {}); ee.emit('click', 1, 'hello', true); ee.off('click'); ``` ## API Simple and similar with `event-emitter`. - `on(evt: string, callback: Function)`: listen an event. - `once(evt: string, callback: Function)`: listen a event only once. - `emit(evt: string, ...parameters: any[])`: emit / trigger an event with parameters. - `off(evt?: string, callback?: Function)`: unsubscribe an event. - `getEvents()`: get all the exist events.