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up vote 1 down vote favorite
1

Not sure if this can even be done, but I'll ask anyway:

Suppose if I have an array of names:

['bob', 'sue', 'dan']

And I want to dynamically create an object from those names:

bob.sue.dan = 5;

Is it possible?

share|improve this question

5 Answers 5

up vote 2 down vote accepted

Here you go, will preserve existing objects:

var namespace = function(name, separator, container){
  var ns = name.split(separator || '.'),
    o = container || window,
    i,
    len;
  for(i = 0, len = ns.length; i < len; i++){
    o = o[ns[i]] = o[ns[i]] || {};
  }
  return o;
};

e.g. usage:

namespace("com.example.namespace");
com.example.namespace.test = function(){
  alert("In namespaced function.");
};

or for your example using an array.

var ns = ['bob', 'sue', 'dan'];
namespace(ns.join('.'));
bob.sue.dan.foobar = true;

or extending an existing object:

var bob = {}
namespace("foo.bar",".",bob);
bob.foo.bar = true;

Edit: updated as requested:

var namespace = function(name, separator, container, val){
  var ns = name.split(separator || '.'),
    o = container || window, i, len;
  for(i = 0, len = ns.length; i < len; i++){
      var v = (i==len-1 && val) ? val : {};
      o = o[ns[i]] = o[ns[i]] || v;
  }
  return o;
};

namespace("bob.sue.dan",null,null,5);
alert(bob.sue.dan);

See working example: http://jsfiddle.net/herostwist/hu6j9/

share|improve this answer
    
I like the elegance of your solution a lot. Is there a way to edit it to give a value in the function itself? –  Manny Fleurmond May 13 '11 at 7:54
    
for example: namespace(name, seperator, container, value) –  Manny Fleurmond May 13 '11 at 8:23
    
updated to accept optional value parameter :) –  herostwist May 13 '11 at 9:03
    
thank you. Not 100% sure how it works, but it does and does well. –  Manny Fleurmond May 13 '11 at 9:22
up vote 2 down vote 
var names = ['bob', 'sue', 'dan'];
var objs = [];

for(var i=0; i<names.length; i++) {
  objs.push(names[i]);
  var val = (i==names.length-1) ? "5" : "{}";
  eval(objs.join(".") + " = " + val);
}

alert(bob.sue.dan);

Demo: http://jsfiddle.net/EpZm2/1/

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up vote 0 down vote

sure you can ... 

var obj = 5;
var yourarray = ['bob', 'sue', 'dan'];

yourarray = yourarray.reverse();
for(e in yourarray) {
    var tmpobj = obj;
    obj = new Object();
    obj[yourarray[e]] = tmpobj;

    // if you already have an object
    if (e+1 == yourarray.length) {
        your_current_existing_object[yourarray[e]] = tmpobj;
    }
}
share|improve this answer
    
What would happen if I already had an object with some populated properties? –  Manny Fleurmond May 13 '11 at 7:07
    
Don't use for..in with arrays unless there is a very good reason and you have protected against the foibles. –  RobG May 13 '11 at 7:11
up vote 2 down vote

Then you can do:

function makeOjectTree(propNames) {
  var name;
  var o = {};
  var result = o;

  for (var i=0, iLen=propNames.length; i<iLen; i++) {
    name = propNames[i];

    if (!o[name]) {
      o[name] = {};
      o = o[name];
    }
  }
  return result;
}
share|improve this answer
up vote -1 down vote

Yes this is possible.

You can define new properties on an object this way:

var obj = {};
obj["bob"] = {};
obj["bob"]["sue"] = {};
obj["bob"]["sue"]["dan"] = 5;

So you can also do it with an array of property names ;)

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1  
that's not dynamically created object –  Teneff May 13 '11 at 7:04
    
especially since I don't want to disturb any other properties that are already in other levels of the structure –  Manny Fleurmond May 13 '11 at 7:06
    
@Teneff I never said it is a dynamically created object. I only showed you the way you could define properties dynamically by a string. And that´s exactly what you need ;) I think -1 is not fair... –  Van Coding May 13 '11 at 7:09

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