I am currently using a licensed copy of IntelliJ idea 13.1. It doesn't seem to support React.js files.
I tried downloading intellij Idea 14.1, even this is not supporting React.js.
Is webstorm the only Idea IDE which supports React.js? I am using groovy on grails, java along with react.js, but these seem to be unsupported in Webstorm.
Is there any way I can use a single IDE for all three?
React.js support is available in Idea 14. Do you have react.js available in your project? The normal way to get completion for API methods is providing the corresponding .js file to Idea - see http://blog.jetbrains.com/webstorm/2014/07/how-webstorm-works-completion-for-javascript-libraries/. Note also that you need to set JavaScript Language Version to 'JSX Harmony' in Settings/Languages&Frameworks/JavaScript to get JSX syntax correctly recognized.