
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


this._map = cmap;
  }
  ToUnicodeMap.prototype = {
    get length() {
      return this._map.length;
    },
    forEach(callback) {
      for (var charCode in this._map) {
        callback(charCode, this._map[charCode].charCodeAt(0));
      }
    },
    has(i) {
      return this._map[i] !== undefined;
    },
    get(i) {
      return this._map[i];
    },
    charCodeOf(value) {