message: Check for undefined, not just truthiness
diff: @@ -30,7 +30,7 @@ export class OdspDeltaStorageService implements api.IDocumentDeltaStorageService
  from?: number,
  to?: number,
  ): Promise<api.ISequencedDocumentMessage[]> {
  - if (this.ops !== undefined && from) {
  + if (this.ops !== undefined && from !== undefined) {
  const returnOps = this.ops;
  this.ops = undefined;
  