title: Javascript truthy equivalent to not undefined, not null and not empty string?
body: <p>
  I found the following legacy Javascript code:</p>
  
  <pre class="lang-js prettyprint-override"><code>function doSomething(parameter) {
      if (parameter != null &amp;&amp; parameter != undefined &amp;&amp; parameter != '') {
          ...
      }
  }
  </code></pre>
  
  <p>I wonder if it is equal to check</p>
  
  <pre class="lang-js prettyprint-override"><code>if(parameter) {
      ...
  }
  </code></pre>
  
  <p>i.e. if it is equal to check if the parameter is truthy. Is there a case when this is not equal?</p>