message: Add type annotation to unspecified array
  The lack of any type on the `ret` variable was causing our typescript compiler to complain.
diff: @@ -604,7 +604,7 @@ export class Builder {
  * @returns list of offsets of each non null object
  */
  createObjectOffsetList(list: string[]): Offset[] {
  - const ret = [];
  + const ret: number[] = [];
  for(let i = 0; i < list.length; ++i) {
  const val = list[i];
  