title: Test for array of string type in TypeScript
body: <p>How can I test if a variable is an array of string in TypeScript?  Something like this:</p>
  
  <pre><code>function f(): string {
      var a: string[] = ["A", "B", "C"];
  
      if (typeof a === "string[]")    {
          return "Yes"
      }
      else {
          // returns no as it's 'object'
          return "No"
      }
  };
  </code></pre>
  
  <p>TypeScript.io here: <a href="http://typescript.io/k0ZiJzso0Qg/2">http://typescript.io/k0ZiJzso0Qg/2</a></p>
  
  <p>Edit: I've updated the text to ask for a test for string[]. This was only in the code example previously.</p>