Language: JavaScript
Label: safe
CWE: CWE-829 \u2014 Inclusion of Functionality from Untrusted Control Sphere
The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.

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

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

    },