title: What a typeof keyword inside function parameters declarations means?
body: <p>I've seen in a presentation how to use Typescript with SAPUI5, and in the example code, it was like this:</p>
  
  <pre><code>sap.ui.define(["sap/ui/core/UIComponent", "sap/m/Select"],
    function(UIComponent, Select: typeof sap.m.Select) {
      "use strict";
      // ...
  });
  </code></pre>
  
  <p>What is the meaning of the <code>typeof</code> keyword in this context? Why didn't the author just write like this:</p>
  
  <pre><code>sap.ui.define(["sap/ui/core/UIComponent", "sap/m/Select"],
    function(UIComponent, Select: sap.m.Select) {
      "use strict";
      // ...
  });
  </code></pre>