Google sheet script, how to check if string already in array?
<p>This indexOf doesnt work anymore nowadays. There is method valueOf but seems to be doing something different. 
Im trying to do something like that :</p>

<pre><code>var emails = [];
emails.push("sample@email");
if (emails.indexOf("sample@email") &gt; 0) { //if this mail exists in array
//do something
}
</code></pre>

<p>Doesnt work this way.</p>