title: I have multi type variable as return type. How can I check if variable is having string[] type
body: <pre><code>public RowData: PricingOrder[] | Notification[] | ActionLog[] | string[];
  </code></pre>
  <p>If <code>RowData</code> is <code>string[]</code> type (<code>Ex-RowData = ['cat','dog','anyother'];</code>)</p>
  <pre><code>if(RowData === string[] type ){
    //perform some string array related operation
   } else {
    //perform custom class array related operation
  }
  </code></pre>