Don't get me wrong, it's great that @calixteman wanted to implement that — JS should definitely be supported! I don't want to come off as rude or attacking.

For starters, JS reference specified in the [commit comment](https://github.com/mozilla/pdf.js/commit/8de98079ca05f8f7001ee077771055a57dc0e948) is outdated. It's version 8.1 from 2007… We're more than decade past that now. We should be implementing [Acrobat DC SDK](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/AcrobatDC_js_api_reference.pdf) ([here](https://help.adobe.com/en_US/acrobat/acrobat_dc_sdk/2015/HTMLHelp/#t=Acro12_MasterBook%2FJS_API_AcroJS%2FJavaScript_API.htm) in a nice HTML version).

Other than that, the Doc object now is only implemented with `info` property with standard fields (`Title`, `Author`, `Subject`, `Keywords`, `Creator`, `Producer`, `CreationDate`, `ModDate` and `Trapped`, case insensitive). But [according to the spec](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/AcrobatDC_js_api_reference.pdf#page=243) (even [in that old version](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/js_api_reference.pdf#page=243)), this object can contain other, non-standard properties, that can be set both in Acrobat interface and in JS (which are case-sensitive then).

Acrobat 9.0 introduced another field to that property, `Authors`, containing semicolon-delimited list of authors.

There are probably other problems with that code due to the outdated spec @calixteman was apparently working on.
expect(metadata.getAll()).toEqual({
      "dc:creator": "ODIS",
      "dc:title": "L'Odissee thématique logo Odisséé - décembre 2008.pub",
      "xap:creatortool": "PDFCreator Version 0.9.6",
    });
  });
  it("should gracefully handle incomplete tags (issue 8884)", function () {
    const data =
      '<?xpacket begin="Ã¯Â»Â¿" id="W5M0MpCehiHzreSzNTczkc9d' +
      '<x:xmpmeta xmlns:x="adobe:ns:meta/">' +
      '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">' +
      '<rdf:Description rdf:about=""' +
      'xmlns:pdfx="http://ns.adobe.com/pdfx/1.3/">' +
      "</rdf:Description>" +
      '<rdf:Description rdf:about=""' +
      'xmlns:xap="http://ns.adobe.com/xap/1.0/">' +
      "<xap:ModifyDate>2010-03-25T11:20:09-04:00</xap:ModifyDate>" +
      "<xap:CreateDate>2010-03-25T11:20:09-04:00</xap:CreateDate>" +
      "<xap:MetadataDate>2010-03-25T11:20:09-04:00</xap:MetadataDate>" +
      "</rdf:Description>" +
      '<rdf:Description rdf:about=""' +
      'xmlns:dc="http://purl.org/dc/elements/1.1/">' +
      "<dc:format>application/pdf</dc:format>" +
      "</rdf:Description>" +
      '<rdf:Description rdf:about=""' +
      'xmlns:pdfaid="http://www.aiim.org/pdfa/ns/id/">' +
      "<pdfaid:part>1</pdfaid:part>" +
      "<pdfaid:conformance>A</pdfaid:conformance>" +
      "</rdf:Description>" +
      "</rdf:RDF>" +