how to configure code completion suggestions to include external JS library only

You need to exclude the directory where all your other libraries reside from indexing (Mark directory as/Excluded) and then add casper.js to JavaScript libraries in Settings | Languages & Frameworks | JavaScript | Libraries

See https://blog.jetbrains.com/webstorm/2014/07/how-webstorm-works-completion-for-javascript-libraries/

Hi @Elena,

That worked.

But I've got a new issue.

The autocompletion works for "new Casper()" defined objects only.

casper = new Casper();

In my case casper is not defined in the code itself but by maven configuration.

Is there a way to instruct InteliJ using a comments or configuration file,  so casper variable would use casper.js for autocompletion.

If not that is a great feature that could be added.

haven't got what you mean,sorry... do you mean that `casper` var is not defined/assigned anywhere in your code? You can try using JSDoc comment then, like

/**
 * @name casper
 * @type {Casper}
 */

yes I meant that, var casper is not defined in my code but injected using maven

The JSDoc works partially 

Doesn't work using casper name

But when I rename the name it works - but that is not a solution

this happens because the `casper` variable is already defined somewhere, and is used when completing methods instead of the var defined in JSDoc... For example, with casperjs installed via NPM, it's defined in samples folder... I was able to get rid of the issue by excluding all files it's defined in, so that the only file added to libraries is `node_modules\casperjs\modules\casper.js`

Thank you  :)

That fixed the issue.