Do you mean that require()
is not resolved? You need to either add require.js
to your project or enable Node.js Globals
predefined library in Settings/Languages and Frameworks/JavaScript/Libraries.
(Edited settings path by @yurik)
In WebStorm 2016.x-2017.x: make sure that the Node.js Core library is enabled in Settings (Preferences) | Languages & Frameworks | Node.js and NPM
In IntelliJ 2018.3.2+ go to Settings (Preferences) | Languages & Frameworks | Node.js and NPM
and enable Coding assistance for Node.js