No error when script check is value set or not.

var input = value ? JSON.parse(value) : {};

return JSON.stringify(input); 

It was suggested to introduce a new predefined variable e. g. "params" that would be an object representing script parameters. This way we will not break existing code that somehow relies on variable named "value" that is expected to be an empty string.

I guess we should be careful in this case and think of the case when "params" variable is already taken in the old code.

There is no problem if the param is used in existing code as it would be redefined without problems.

Indeed, JS can do wonders:

var params = 5;
console.log("params=" + params);

var params = 'foo';
console.log("params=" + params);

Output:

params=5
params=foo

No warnings issued.