How to browse and tweak objects using a string path. 😄 (require Underscore.js for the _.isString)

exemple.js

var target = {
  foo: {
    bar: {
      baz: [
        'madness'
      ]
    }
  }
};

deepAccess(target, 'foo.bar.baz').push('sparta');

console.log(target) //→ {foo:{bar:{baz:['madness', 'sparta']}}}

index.js

function deepAccess(obj, path){
  if(_.isString(path)){
    path = path.replace(/\[/g, '.').replace(/\]/g, '').split('.');
  }
  return path.length === 1 ? obj[path.shift()] : deepAccess(obj[path.shift()], path);
}

Underscore-less version

function deepAccess(obj, path){
  if(Object.prototype.toString.call(path)==="[object String]"){
    path = path.replace(/\[/g, '.').replace(/\]/g, '').split('.');
  }
  return path.length === 1 ? obj[path.shift()] : deepAccess(obj[path.shift()], path);
}