As of React 15.5 React.createClass is deprecated and is due to be removed in React 16.0
Unfortunately it seems react-selectize is not using babel so porting the code to use ES6 classes is not possible without messing with the build process. Maybe it is time to consider porting the build process to webpack? Get rid of the gulpfile and use npm scripts that call webpack instead?
As of React 15.5 React.createClass is deprecated and is due to be removed in React 16.0
Unfortunately it seems react-selectize is not using babel so porting the code to use ES6 classes is not possible without messing with the build process. Maybe it is time to consider porting the build process to webpack? Get rid of the gulpfile and use npm scripts that call webpack instead?