Javascript: Get deep value from object by passing path to it as string [duplicate]

Question

Possible Duplicate:
Accessing nested JavaScript objects with string key

Maybe the title is not clear enough, I just didn't know how to specify what I'm looking for and my English is really bad, sorry.

I'm trying to create function that returns object value, but also plays nice with nested objects. For example:

var obj = {
  foo: { bar: 'baz' }
};

I want to access the value of obj.foo.bar by suppling the string "foo.bar" to the function.

function(obj, path) {
  // Path can be "foo.bar", or just "foo".
}

Thanks!

Answer 1

This works correctly:

var deep_value = function(obj, path){
    for (var i=0, path=path.split('.'), len=path.length; i<len; i++){
        obj = obj[path[i]];
    };
    return obj;
};

Here is the proof / demo: jsfiddle.net/tadeck/5Pt2q/13/

EDIT: I have removed redundant variables, shortened the code.

Answer 2

Consider this:

var obj = {
  foo: { bar: 'baz' }
};

function deepFind(obj, path) {
  var paths = path.split('.')
    , current = obj
    , i;

  for (i = 0; i < paths.length; ++i) {
    if (current[paths[i]] == undefined) {
      return undefined;
    } else {
      current = current[paths[i]];
    }
  }
  return current;
}

console.log(deepFind(obj, 'foo.bar'))

Answer 3

You mean something like this ? It is a recursive version

function recLookup(obj, path) {
    parts = path.split(".");
    if (parts.length==1){
        return obj[parts[0]];
    }
    return recLookup(obj[parts[0]], parts.slice(1).join("."));
}

See http://jsfiddle.net/kExSr/

Answer 4

something like:

function(obj, path) {
  var current=obj; 
  path.split('.').forEach(function(p){ current = current[p]; }); 
  return current;
}

Answer 5

You'd want to split the string on the dot and then repeatedly index into the object, e.g. along the lines of:

function goDeep(obj, path) {
    var parts = path.split('.'),
        rv,
        index;
    for (rv = obj, index = 0; rv && index < parts.length; ++index) {
        rv = rv[parts[index]];
    }
    return rv;
}

Live example

That works because you can access the property of an object in a couple of different ways: There's dotted syntax using a literal (obj.foo), and there's bracketed syntax using a string (obj["foo"]). In the latter case, the string can be the result of any expression, it doesn't have to be a string literal. In in all of the, rv is set to the same value:

rv = obj.foo.bar;
// Or
rv = obj.foo["bar"];
// Or
f = "foo";
rv = obj[f].bar;
// Or
s = "b";
rv = obj.foo[s + "ar"];