Looking for javascript techniques [closed]

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I'm trying to learn some fresh and hacky javascript techniques and on my quest to do so, here is a function I mocked up:

function doAction(index) {
    for(var a = Array.prototype.slice.call(arguments, 1), 
            i = 0, r = [], l = a.length; i < l; i++) 
        r.push(a[i][index]);
    return r;
}

doAction(2, ['a','b','c'],['a','b','c'],['a','b','c']) //==> ["c", "c", "c"]

This is basically what it does: get every nth element from a number of arrays and return them in a new one.

I would like to improve this function with freaky ninja-style ideas, not necessarily shorten the code, but rather optimize it. (You most probably already noticed the infamous Array.prototype.slice thingy);

As English is not my native tongue, I would also like a decent name for the action performed by this function. Thanks in advance 开发者_如何学运维guys (and women!)

Oh, here's a Fiddle: http://jsfiddle.net/Exv7Z/

EDIT: Talking about optimizing things... (Idea from the genius in the comments)

function doAction(index) {
    return Array.prototype.slice.call(arguments, 1).map(function(b) {
        return b[index];
    });
}

---

There is not much to optimize I think, but i'll do two change

• First, declaring a real argument instead of using some that aren't here
• Second, I'd put the variable initialisation outside of the for.

Those two points aren't really optimization, but it's rather a matter of readability (and of taste maybe)

The code would be something like

function doAction(index,a) {
   var r = [], l = a.length;
   for(var i=0; i < l; i++) r.push(a[i][index]);
   return r;
}

and the call would be doAction(2, [['a','b','c'],['a','b','c'],['a','b','c']]);

---

It can be simplified like this as there is no need to copy the arguments array. It only needs to be copied of it needs to be modified:

function doAction(index) {
    var r = [];
    for(var i = 1; i < arguments.length; i++) r.push(arguments[i][index]);
    return r;
}

or if you want to keep the len variable, it can be this:

function doAction(index) {
    var r = [];
    for(var i = 1, len = arguments.length; i < len; i++) r.push(arguments[i][index]);
    return r;
}

jsFiddle here: http://jsfiddle.net/jfriend00/Z22w7/.

As for a name, you might call it multiSlice() or multiIndex().