Unexpected token error with executeScript_Sandbox

Ui.Vision General Discussion
1 
var value = "${variable}";

if (value.indexOf(",") !== -1) {
    return value.split(",")[0].trim();
} else {
    return value;
}

What is the alternative?
2

${...} in script commands is inserted as an already-quoted string, so drop your own quotes:

var value = ${variable}; 
if (value.indexOf(",") !== -1){ 
return value.split(",")[0].trim(); 
} else { 
return value; 
}

In Firefox, the sandbox rejects split (along with match/replace/exec/search) with E501 … Firefox does not support regular expressions

A cross-browser version that avoids split is:

var value = ${variable};
var i = value.indexOf(",");
return i !== -1 ? value.substring(0, i).trim() : value;