When is RequireJS' require call asynchronous? When is it synchronous?

Question

I use RequireJS to load my modules in one of my projects. I see around the web different ways to require modules using the require call (and not define

Answer 1

I don't know requirejs. But I think it's possible to load module in both sync and async ways.

function require(name,cb){
    if(cb !== undefined){
        requireAsync(name,cb);
    }else{
        requireSync(name);
    }
}