reactjs - passing function as prop, undefined error -

i m trying pass prop child component.

onchangenumber: e => {   console.log(e); };  class mydrinking extends react.component {   render() {     return (       <flexible>         <lydslider           {...sceneconfig}           onchangenumber={this.onchangenumber.bind(this)}           value={sceneconfig.slidernumbervalue}         />       </flexible>     );   } } 

keep getting this.props.onchangenumber not function.

any ideas?

because function not defined property inside of class.

class mydrinking extends react.component {     constructor() {         super();         this.onchangenumber = this.onchangenumber.bind(this);     }     onchangenumber(e) {         console.log(e);     }     render() {         return (             <flexible>               <lydslider                 {...sceneconfig}                 onchangenumber={this.onchangenumber}                 value={sceneconfig.slidernumbervalue}               />             </flexible>         );     } }