build/build.js
function firstDefined() {
  for (var i = 0, l = arguments.length, v; i < l; i++) {
    v = arguments[i];
    if (typeof v !== 'undefined') return v;
  }
  return v;
}
function firstDefined() {
  for (var i = 0, l = arguments.length, v; i < l; i++) {
    v = arguments[i];
    if (typeof v !== 'undefined') return v;
  }
  return v;
}
function firstDefined ( ) { for ( var i = 0 , l = arguments . length , v ; i < l ; i ++ ) { v = arguments [ i ] ; if ( typeof v !== 'undefined' ) return v ; } return v ; }
Choose the first defined value

@api private
Choose the first defined value