walk_path.js

/**
 * Given an object and an array of keys, walk over the keys on the object.
 * 
 * For example:
 * ```js
 * walk({ a: { b: [ 0, { c: 2 } ] } }, [ 'a', 'b', 1, 'c' ]) // returns 2
 * ```
 * 
 * @param {Object} obj
 * @param {String|Number[]} path
 * @return {*}
 */
function walk (obj, path) {
  var result = obj
  var i, j, key
  
  for (i = 0, j = path.length; i < j; i++) {
    key = path[i]
    if (typeof result === 'object' && result !== null && key in result)
      result = result[key]
    else {
      result = void 0
      break
    }
  }
  
  return result
}