@cfxlabsinc/b2b-services
    Preparing search index...

    Variable PREVIEW_XLSX_MAX_UNZIPPED_BYTESConst

    PREVIEW_XLSX_MAX_UNZIPPED_BYTES: number = ...

    And parses one only when it really unpacks to no more than this. The reader below holds the unpacked parts plus one part's text, so a read stays near 10 MB.