JavaScript Variables, If Statement, Regex

I have the following:

var p_1;
var re = "value_to_test";

//////////////////////////////////

if("/.*/i" + re + "/.*/i".test(formula_label)){

    p_1 = 'hi';

else{

    p_1 = 'bye';

}

I get a syntax error when I do this though. The error message is not very helpful. What am I doing wrong?

All the error message says is

Syntax error