c9-core/node_modules/c9/has-internal-domain.js

if (define === undefined) {
    var define = function(fn) {
        fn(require, exports, module);
    };
}

define(function(require, exports, module) {
    "use strict";

    var _ = require("lodash");

    var internalDomain = ['c9.io', 'cloud9beta.com'];

    function hasInternalDomain(email) {
        if (!email) return false;

        var emailElements = email.split("@");
        var emailDomain = emailElements[emailElements.length - 1];

        return _.contains(internalDomain, emailDomain);
    }

    module.exports = hasInternalDomain;
});