Iterate through Nested JavaScript Objects

Question

I'm trying to iterate through a nested object to retrieve a specific object identified by a string. In the sample object below, the identifier string is the "label" property. I can't wrap my head around how to iterate down through the tree to return the appropriate object. Any help or suggestions would be greatly appreciated.

var cars = {
  label: 'Autos',
  subs: [
    {
      label: 'SUVs',
      subs: []
    },
    {
      label: 'Trucks',
      subs: [
        {
          label: '2 Wheel Drive',
          subs: []
        },
        {
          label: '4 Wheel Drive',
          subs: [
            {
              label: 'Ford',
              subs: []
            },
            {
              label: 'Chevrolet',
              subs: []
            }
          ]
        }
      ]
    },
    {
      label: 'Sedan',
      subs: []
    }
  ]
}

Answer 1

You can create a recursive function like this to do a depth-first traversal of the cars object.

var findObjectByLabel = function(obj, label) {
    if(obj.label === label) { return obj; }
    for(var i in obj) {
        if(obj.hasOwnProperty(i)){
            var foundLabel = findObjectByLabel(obj[i], label);
            if(foundLabel) { return foundLabel; }
        }
    }
    return null;
};

which can be called like so

findObjectByLabel(car, "Chevrolet");