IDE doesn't recognize custom plugins

[JoniJnm]

I have a custom plugin, it works but PHPStorm doesn't recognize it as plugin.

Plugin:

define([
    'consts/locale'
], function(locale) {
    'use strict';
    
    const lang = locale.lang;
    
    return {
        load: function(name, req, onLoad, config) {
            if (config.isBuild) {
                onLoad('en');
                return;
            }
            
            req(['langs/'+lang], function() {
                onLoad(lang);
            });
        }
    };
});

Other file:

define(function(require, exports, module) {
    'use strict';
    
    require('user-lang');
    require('user-lang!'); //it's a plugin!
});

Using:

• PHPStorm 2017.2.1
• Require.js plugin 0.25

What is wrong?