index.js
function setDefault(obj, key, val) {
  if (_.isUndefined(obj[key])) {
    obj[key] = val;
    return val;
  }
  return obj[key];
}
function setDefault(obj, key, val) {
  if (_.isUndefined(obj[key])) {
    obj[key] = val;
    return val;
  }
  return obj[key];
}
function setDefault ( obj , key , val ) { if ( _ . isUndefined ( obj [ key ] ) ) { obj [ key ] = val ; return val ; } return obj [ key ] ; }
If given key is set in the object it returns the associated value, otherwise it sets the value to val and returns it.
If given key is set in the object it returns the associated value otherwise it sets the value to val and returns it .