Language: JavaScript
Label: safe
CWE: CWE-352 \u2014 Cross-Site Request Forgery (CSRF)
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

Code:
    isExists: function(product_id, whereToCheck=".productID") {

        return $(whereToCheck).filter(function() { return this.value === product_id; }).length > 0;

    },