CODEWITHSUNDEEP
javascriptfunctionsyntaxreadability
cc young
cc young

Reputation: 20213

in javascript, same code parsing arguments in different functions - copy or not?

Have a series of functions, each of which parses its arguments identically. right now this parsing chunk is cut and pasted to the beginning of each function. Is there a better way to do this?

Post.update = function( e ) {

        // parse args
        var e, el, orig_el, args, render, callBack;
        for( var i=0; i<arguments.length; i++ ) {
                if( arguments[i] instanceof HTMLElement ) orig_el = arguments[i];
                else if( arguments[i] instanceof Render ) render = arguments[i];
                else if( arguments[i] instanceof Event ) {
                        e = arguments[i];
                        orig_el = orig_el || e.target;
                }
                else if( typeof arguments[i] == 'function' )  callBack = arguments[i];
        }

        // Post.update work here
}

Post.verify = function( e ) {

       // parse args
       ...

       // Post.verify work here
}

The reasons arguments are parsed instead of passed individually are that, with five+ possible args

So my goal is to abstract the parse section of the functions while maintaining the clarity of the function calls as they are now.

Upvotes: 0

Views: 955

Answers (4)

Jose Faeti
Jose Faeti

Reputation: 12294

Of course you should use a function to prevent copy and paste all that code!

What if you want to change a single character in the code? Right now you have to copy and paste everything again! That's just no good really.

Stick that code into a function and call it everytime, this way when you change something in the code function, the change will be reflected to every place where that function is being used.

Are you worried about passing so many arguments into the function? You really have to be worried, cause passing so many arguments into a function is really bad. Just stick all your arguments into a single object, and only pass that object to the function, like this:

var arg = {
    arg1: 'bla bla bla',
    arg2: 4,
    //.....
};

// call the function passing only one parameter
myFunction( arg );

Then inside the function you will have a single argument and you can access all the others like this:

function myFunction( arg ) {
    // arg.arg1
    // arg.arg2 ...
}

Upvotes: 1

Raynos
Raynos

Reputation: 169401

Rather then parsing 5 arguments out of a function you should realise functions should not have more then 3 arguments.

What you want to do instead is have the last argument be an object

Post.update = function(ev, obj) {
  // obj.el
  // obj.render
  // obj.ev
  // obj.cb
}

Then just have a function for that can be re-used 

Post.parseObj = function(obj) {
  ...
} 

Post.update = function(ev, obj) {
  obj = Post.parseObj(obj);
}

Upvotes: 1

ChristopheCVB
ChristopheCVB

Reputation: 7315

Why not using a Post.parseArgs function ?

Post.parseArgs = function(args)
{
    // parse args
    var e, el, orig_el, args, render, callBack;
    for( var i=0; i<arguments.length; i++ ) {
            if( arguments[i] instanceof HTMLElement ) orig_el = arguments[i];
            else if( arguments[i] instanceof Render ) render = arguments[i];
            else if( arguments[i] instanceof Event ) {
                    e = arguments[i];
                    orig_el = orig_el || e.target;
            }
            else if( typeof arguments[i] == 'function' )  callBack = arguments[i];
    }
    // return what you want...
}

Upvotes: 0

Quentin
Quentin

Reputation: 943579

Define the functions once and reuse them

var update = function (e) { /* etc */ }
Post.update = update;

Upvotes: 0

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