REACTJS - Best practise with ES6 - A Component calling a method it owns with a parameters in scope at definition

gistfile1.txt

// A component calling a method with parameters; Using ES6, so no need for bind as the arrow function does this

          <select onChange={(event)=>this._handleSelectChange(x, index, event)} className="form-control" name={"os"+index}>
            {eachOption}
          </select>

// ES5 way using bind
          <select onChange={this._handleSelectChange.bind(this,index)} className="form-control" name={"os"+index}>
            {eachOption}
          </select>