Javascript Dynamic Arrays and Object

Question

Is this possible?

So I need to have an array with a dynamic name and content what can be extended and accessed.

object = {};
var two = ['thing', 'thing2'];
for(one in two){
 object[two[one]] = [];
}

If yes but not in this way, then how?

• strager: Eh? I'm not sure what you're asking. Also, iterating an Array with for-in is considered bad practice; use a C-style for loop or use Array.prototype.forEach if available.
• Adam Halasz: Sorry, it's really hard to explain for me :\
• Phrogz: Note that the code sample you show there declares a global one variable, unless you have var one elsewhere in your function. Best practice for iterating properties of an object is for (var prop in obj){ if (obj.hasOwnProperty(prop)){ ... } }.

Answer 1

This is definitely doable, just make sure that the object owns the property and it's not inherited from higher up in the prototype chain:

object = {};
var two = ['thing', 'thing2'];

for..in:

for(var one in two){
 if(two.hasOwnProperty(one))
 object[two[one]] = [];
}

for:

for(var i = 0; i < two.length; i++)
 object[two[i]] = [];

• Phrogz: You are missing a var on one, causing it to be globally defined (and potentially collide).
• Jacob Relkin: @Phrogz, Oops. Missed that one. Thanks!

Answer 2

var object = {};
var props = 'thing thing2'.split(' ');
for (var i=0,len=props.length;i<len;++i){
 object[props[i]] = [];
}