Using numbers for names of javascript object elements

Question

Is the following code valid?

var i;
var objs={};
for (i=0; i <10; i++)
{
   objs.i=new FooObject();
}

alert(objs.4.someMethod());

If not, how should it be rewritten to accomplish what I want?

Answer 1

var i; 
var objs = new Array();

for(i = 0; i < 10; i++)
{
   objs.push(new FooObject());
}


objs[4].someMethod();

Answer 2

You cannot use numericals for variable names ¹. If you want to reference an item by a numerical value, use an array ². You can then access items by their key in the array. If you want to cycle through, you can use the for...in option ³. It won't matter if your keys are sequential and contiguous:

var x;
var myItems = new Array();
myItems[0] = "Foo";
myItems[9] = "Bar";
myItems[5] = "Fiz";

for (x in myItems) {
  alert(myItems[x]);
}

¹ http://www.w3schools.com/js/js_variables.asp
² http://www.w3schools.com/js/js_obj_array.asp
³ http://www.w3schools.com/js/tryit.asp?filename=tryjs_array_for_in

Answer 3

You should edit your code as following:

var i;
var objs = {};
for (i = 0; i < 10; i++) {
  objs[i] = new FooObject();
}

alert(objs[4].someMethod());

Answer 4

You can't use numbers as variable names, because straight up numbers exist as their own object set in Javascript (i.e, you could think of 4 as already being a global variable that you can't override).