javascript - Setting a depth in an object literal by a string of dot notation? - Stack Overflow

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There are plenty of solutions out there to check/access an object literal giving a string of dot notation, but what I need to do is SET an object literal based on a string of dot notation. It is very technical why I need to do this, and if it isn't feasible I will e up with a different solution.

Here is what I'd like to do:

var obj = { 
   'a': 1, 
   'b': 2, 
    'c': { 
      'nest': true 
    } 
};

I'd like a function that would work something like this:

setDepth(obj, 'c.nest', false);

That would change the obj to this:

var obj = { 
   'a': 1, 
   'b': 2, 
    'c': { 
      'nest': false
    } 
};

I've been trying to an hour and haven't been able to e up with a good solution yet. Another help would be so greatly appreciated!

There are plenty of solutions out there to check/access an object literal giving a string of dot notation, but what I need to do is SET an object literal based on a string of dot notation. It is very technical why I need to do this, and if it isn't feasible I will e up with a different solution.

Here is what I'd like to do:

var obj = { 
   'a': 1, 
   'b': 2, 
    'c': { 
      'nest': true 
    } 
};

I'd like a function that would work something like this:

setDepth(obj, 'c.nest', false);

That would change the obj to this:

var obj = { 
   'a': 1, 
   'b': 2, 
    'c': { 
      'nest': false
    } 
};

I've been trying to an hour and haven't been able to e up with a good solution yet. Another help would be so greatly appreciated!

• javascript

Share Improve this question Follow edited Apr 20, 2012 at 20:56 Niko 26.7k99 gold badges9696 silver badges112112 bronze badges asked Apr 20, 2012 at 20:44 mattacularmattacular 1,8891313 silver badges1717 bronze badges 3

• possible duplicate of Javascript nested objects from string and JavaScript function to create a structured Object from a String? – Matt Ball Commented Apr 20, 2012 at 20:48
• It isn't a duplicate of those, I want to modify a certain property of an existing object and not touch the rest of the object. So the obj I made above already has values set: 'obj.a', 'obj.b', 'obj.c' and i just want to make a change to obj.c.nest – mattacular Commented Apr 20, 2012 at 20:57
• It's almost exactly the same logic, though. – Matt Ball Commented Apr 20, 2012 at 21:07

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 6

My version:

function setDepth(obj, path, value) {
    var tags = path.split("."), len = tags.length - 1;
    for (var i = 0; i < len; i++) {
        obj = obj[tags[i]];
    }
    obj[tags[len]] = value;
}

Working demo: http://jsfiddle/jfriend00/Sxz2z/

This is one way of doing it:

function setDepth(obj, path, value) {
    var levels = path.split(".");
    var curLevel = obj;
    var i = 0;
    while (i < levels.length-1) {
        curLevel = curLevel[levels[i]];
        i++;
    }
    curLevel[levels[levels.length-1]] = value;
}

Working demo.

I modified Elliot's answer to let it add new nodes if they don't exist.

var settings = {};

function set(key, value) {
  /**
         * Dot notation loop: http://stackoverflow./a/10253459/607354
         */
  var levels = key.split(".");
  var curLevel = settings;
  var i = 0;
  while (i < levels.length-1) {
    if(typeof curLevel[levels[i]] === 'undefined') {
      curLevel[levels[i]] = {};
    }

    curLevel = curLevel[levels[i]];
    i++;
  }
  curLevel[levels[levels.length-1]] = value;

  return settings;
}

set('this.is.my.setting.key', true);
set('this.is.my.setting.key2', 'hello');

Just do it like this:

new Function('_', 'val', '_.' + path + ' = val')(obj, value);

In your case:

var obj = { 
   'a': 1, 
   'b': 2, 
    'c': { 
      'nest': true 
    } 
};

new Function('_', 'val', '_.c.nest' + ' = val')(obj, false);

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