function isBinary(data) {
            var reader = new DataView(data);

            // US-ASCII ordinal values for `s`, `o`, `l`, `i`, `d`
            var solid = [115, 111, 108, 105, 100];
            for (var off = 0; off < 5; off++) {
              // If "solid" text is matched to the current offset, declare it to be an ASCII STL.
              if (matchDataViewAt(solid, reader, off)) return false;
            }

            // Couldn't find "solid" text at the beginning; it is binary STL.
            return true;
          }
This function parses the Binary STL files.
https://en.wikipedia.org/wiki/STL_%28file_format%29#Binary_STL

Currently there is no support for the colors provided in STL files.