decodePixels(fn) {
  return zlib.inflate(this.imgData, (err, data) => {
    if (err) {
      throw err;
    }
    ...

const PDFDocument = require('pdfkit');
const fs = require('fs');
const zlib = require('zlib');

// Construct a PNG which IDAT payload is not a valid zlib stream
function chunk(type, data) {
  const len = Buffer.alloc(4);
  len.writeUInt32BE(data.length);
  const body = Buffer.concat([Buffer.from(type, 'ascii'), data]);
  const crc = Buffer.alloc(4);
  crc.writeUInt32BE(zlib.crc32 ? zlib.crc32(body) : 0);
  return Buffer.concat([len, body, crc]);
}

const ihdr = Buffer.alloc(13);
ihdr.writeUInt32BE(1, 0); // width
ihdr.writeUInt32BE(1, 4); // height
ihdr[8] = 8; // bit depth
ihdr[9] = 6; // color type: RGBA (forces pdfkit to decode pixels)
const corruptPng = Buffer.concat([
  Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]),
  chunk('IHDR', ihdr),
  chunk('IDAT', Buffer.from([0xde, 0xad, 0xbe, 0xef])), // garbage deflate data
  chunk('IEND', Buffer.alloc(0)),
]);

const doc = new PDFDocument();
doc.pipe(fs.createWriteStream('/dev/null'));

try {
  doc.image(corruptPng, 0, 0);
  doc.end();
} catch (err) {
  console.log('Caught:', err.message); // never reached
}