如果选择值为空，我可以神奇地使选择器不起作用吗？

Question

Background: I have a function that I call like this:

hide_modules('string1','string2');

The function is something like:

function hide_modules(param1,param2) {
       MM.getModules()
         .withClass(param1)
         .exceptWithClass(param2)
         .enumerate(function(module) {
           module.hide(
             // some other code
           );
         });
}

Most of the time I call the function with values as shown above. Sometimes I do not want 'string1' to have a value and I'd like the my function to not use that first selector, effectively like this:

   MM.getModules()
     // .withClass(param1)
     .exceptWithClass(param2)
     .enumerate(function(module) {
       module.hide(
         // some other code
       );
     });

I've tried just calling it with an empty string, 0, false as param1 but the end result class selection is not what I want. Sometimes I also call it with param2 empty and not wanting to have the param2 related selector used either.

So the question is: Without writing a big if-then-else statement, is there some fancy way I can make those selectors non-functional (the equivalent of commenting it out like above) when the param1 and/or param2 values are not specified?

---

The supporting code that my function calls is provided for me in a 3rd party library that I can't change. I include some of the relevant parts here as it may help with the answer:

var withClass = function (className) {
    return modulesByClass(className, true);
};
var modulesByClass = function (className, include) {
    var searchClasses = className;
    if (typeof className === "string") {
        searchClasses = className.split(" ");
    }

    var newModules = modules.filter(function (module) {
        var classes = module.data.classes.toLowerCase().split(" ");

        for (var c in searchClasses) {
            var searchClass = searchClasses[c];
            if (classes.indexOf(searchClass.toLowerCase()) !== -1) {
                return include;
            }
        }

        return !include;
    });

Answer 1

Since js doesn't supports function overloading, the only way is to validate your parameters inside your method. Check for truthy and ternary operator will do the trick

      var modules = MM.getModules();
      modules = param1 ? modules.withClass(param1) : modules;
      modules = param2 ? modules.exceptWithClass(param2) : modules;
      modules.enumerate(function(module) {
      module.hide(
         // some other code
       );
     });

to skip first parameter

hide_modules(null,'string2');

to skip second parameter

hide_modules('string1');