Which approach is better: function.apply(<this>, args) or having a function to accept <this> as argument?

Question

Let's say that I have a functionA defined like this:

functionA = function(myObject, someParams) {
  myObject.save_some_data = someParams;
  myObject.processed = true;
}

I can then call it and pass an object to work on as functionA(someObject, someParams).

I can, however, transform this example with apply():

functionA = function(someParams) {
  this.save_some_data = someParams;
  this.processed = true;
}

functionA.apply(someObject, [someParams]);

Both approaches seems to be achieving the same goal, or am I missing something?

But since apply() does exist in JavaScript, what are the benefits of using it instead of having my functions accept this as a first argument?

Answer 1

apply is going to use someParams as an array of arguments; call would actually do the same thing:

functionA.call(someObject, someParams);

There are no benefits except for style. Passing someObject as an argument is probably going to make more sense in most cases, but it’s really up to you and which one you like best.