reactjs - Handle Change of FormControl React -

hey have text box/formcontrol that's supposed update field in json in this.state. wondering if there better way onchange?

<formcontrol    type='text'    placeholder='enter'    defaultvalue={this.state.form.name}   onchange={this.handlechange.bind(this, 'name')} /> </formgroup> 

`

handlechange(change, event) {     var tochange = this.state.form;     tochange[change] = event.target.value;     this.setstate({form: tochange});   } 

optimise handlechange method below. (replace 'username' fieldname like...)

<formcontrol    type='text'   name='username'    placeholder='enter'    defaultvalue={this.state.form.username}   onchange={this.handlechange.bind(this)} /> </formgroup>  handlechange(event) {     let fieldname = event.target.name;     let fleldval = event.target.value;     this.setstate({form: {...this.state.form, [fieldname]: fleldval}})   }