
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)


break;
        }
        var glyphsUnicodeMap = getGlyphsUnicode();
        var glyphUnicode = glyphsUnicodeMap[glyphName];
        
        var charcode = 0;
        if (this.composite && this.cMap.contains(glyphUnicode)) {
          charcode = this.cMap.lookup(glyphUnicode);
        }
        
        if (!charcode && this.toUnicode) {
          charcode = this.toUnicode.charCodeOf(glyphUnicode);
        }
        
        if (charcode <= 0) {
          charcode = glyphUnicode;
        }
        
        width = this.widths[charcode];
        if (width) {
          break; 
        }
      }
      width = width || this.defaultWidth;
      return shadow(this, "spaceWidth", width);
    },
    /**
     * @private
     */
    _charToGlyph(charcode, isSpace = false) {