Accessing Javascript Array without using [] Brackets

Question

I'm trying to write some javascript in an environment where square brackets are used for macro replacement, so they can't be used as normal in the script.

If I create an array as an object with new Array() I can use push() and pop() to access the elements, but for native arrays I can't figure out a way to get to the elements without using brackets. For example, the array returned from:

var allElements = document.getElementsByTagName("*");

Is there a way to assign a native array into an Array object so I can use push() and pop(), or is there another way to get inside?

Answer 1

For NodeList collections you can use .item():

var allElements = document.getElementsByTagName("*");
var firstItem = allElements.item(0);

Source: NodeList

Answer 2

You could define a macro that inserts the [] braces. This might be possible. :-)

However, I am wondering why you still use this environment - even Notepad might be more comfortable then.

Answer 3

First of all, the JavaScript engine will convert literals to objects for you (it does this behind the scenes)

var arr = [1,2,3];
alert( arr.pop() );

Secondly, understand that the return value from document.getElementsByTagName() is not an array. It's an HTMLCollection.

Answer 4

yes, you can use prototype and slice method for example (Does not work in IE):

var index = 1;
Array.prototype.slice.call(allElements,index,index+1);

For IE, the only way I can think of is to copy all elements from collection to the array:

var newarr = new Array();
for(var i=0;i<allElements.length;i++){
    newarr.push(allElements[i]);
}

Or, you can use this function (Works in IE and Firefox):

window.atIndex = function(array,index){
    return eval("array" + String.fromCharCode(91) + String(index) + String.fromCharCode(93));
}

Get any item by using atIndex(allElements,0);

Answer 5

for loops you can iterate through the collection like
for(var item in array){
doStuff(item);
}

You could also use Jquery's makeArray function
var newArray = $.makeArray(array);

I'm assuming you have no choice in your environment square braces are a normal thing in tons of programming languages. The ideal solution is use an environment that doesn't limit your programming

Answer 6

arr = [1, 2, 3]; //just a dummy array, I assume you don't use square brackets to assign an array in your code
el0 = arr.slice(0,1).pop(); //returns 0th element
el1 = arr.slice(1,2).pop(); //returns 1st element
...

Don't have IE here, but it works fine in Firefox.