Search up through an angular scope to find the object holding a given named scope variable

key_search.js

function findKey(searchObject, scopeVariableName) {
  for (var objectKey in searchObject) {
      if (objectKey === scopeVariableName) {
          return searchObject;
      } else if (objectKey === '$parent' && searchObject[objectKey] instanceof Object) {
          if (searchObject.hasOwnProperty(objectKey)) {
              var result = findKey(searchObject[objectKey], scopeVariableName);
              if (result) { 
                return result; 
              }
          }
      }
  }

  return null;
};