&gt; JS is in exactly the same league with Python and Ruby and Perl other similar dynamic languages<p>I don&#x27;t know about Perl, but Python and Ruby both give you a type error for [] + {} or {} + [] or 1 + &quot;1&quot;. And both Python and Ruby give you an error when you do something like &quot;&quot;.notavalue, whereas javascript just gives you undefined. They might look similar enough visually, but under the hood they are different in terms of strictness and types.