Silent error on parse semi-transparent content

Hello, recently I found bug with parsing some .pdf files. If file have symbols colored in semi-transparent color, a program just stops without any error messages. Here's code which stops silent (declaration.pdf - "unparsable" document):

let fs = require('fs'),
    PDFParser = require("pdf2json");

let pdfParser = new PDFParser(this, 1);

pdfParser.on("pdfParser_dataError", errData => console.error(errData.parserError) );
pdfParser.on("pdfParser_dataReady", pdfData => {
    fs.writeFile("./content.txt", pdfParser.getRawTextContent());
});

pdfParser.loadPDF("./Declaration.pdf");

So, after I tried to parse document directly with pdf2json:
node pdf2json.js "../../documents/whitepaper/47/WP_En.pdf" "../../"
And I got some errors:

Warning: Unhandled rejection: Error: JPEG error: Unsupported color mode (4 components)
Error: JPEG error: Unsupported color mode (4 components)
    at error (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:195:9)
    at JpegStream_ensureBuffer [as ensureBuffer] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:25571:7)
    at JpegStream.DecodeStream_getBytes [as getBytes] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:24875:14)
    at PDFImage_getImageBytes [as getImageBytes] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:21009:25)
    at PDFImage_fillRgbaBuffer [as fillRgbaBuffer] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:20941:27)
    at PDFImage_getImageData [as getImageData] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:21004:12)
    at eval (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:7125:34)
    at Object.eval [as onResolve] (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:20657:7)
    at Object.runHandlers (eval at <anonymous> (app\node_modules\pdf2json\lib\pdf.js:64:1), <anonymous>:864:35)
    at ontimeout (timers.js:466:11)

In a nutshell, my solution was to comment 2 lines(832-833) in /base/core/jpg.js:

if (!this.adobe)
    throw 'Unsupported color mode (4 components)';

After that I successfully parsed my document.

So, @modesty, can you fix this or just remove?

Reproduce the failure with Declaration.pdf or the pdf2json.js command shown in the issue, then inspect /base/core/jpg.js around lines 832-833 and the pdfParser_dataError handling path. Verify how four-component JPEGs are handled and ensure parsing reports a useful error or completes without silently stopping; retest the reported document and the existing sample command.