title: Regex to check input is not empty plus it's alphanumeric?
body: <p>I need a single regex to check if input must not be empty plus the input has alphanumeric characters only.</p>
  
  <p>I know the alphanumeric part,<code>^[\s+0-9a-zA-Z]+$</code>, but I am not sure about the not empty requirement.</p>
  
  <p>I can only use a single expression and I can't use any language function.</p>