import React from 'react'; import { render } from 'react-dom'; import AsyncButton from 'react-async-button';  export default App extends Component {   clickHandler() {     return new Promise((resolve, reject) => {       // some async stuff       setTimeout(resolve, 500);     })   }    render() {     return (       <AsyncButton         className="btn"         text="Save"         pendingText="Saving..."         fulFilledText="Saved Successfully!"         rejectedText="Failed! Try Again"         loadingClass="isSaving"         fulFilledClass="btn-primary"         rejectedClass="btn-danger"         onClick={this.clickHandler}        />     )   } }  render(<App/>, document.getElementById('root'));