Utility to convert binary array buffer to usable card information.

CardUtils.js

// buffer is an array buffer, this routine will apply a Uint8Array to it.
// numbers is the numbers of the game (0 or 75 is 75, or 90 number which is different)
//  call with '75' 
function MakeCardFromBuffer( buffer, numbers ) {
  buffer = new Uint8Array(buffer);
  //console.log( "Length...", buffer.byteLength, buffer[0] );
  if( buffer.byteLength == 12 ) {
    if( !numbers || numbers === 75 ) {
      var card = [[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0]];
      var row,col, n = 0;
      if( !buffer )
        return undefined;
      //console.log( "doing for buffer", buffer)
      for( col = 0; col < 5; col++ ) {
        var base = col * 15;

        for( row = 0; row < (col==2?4:5); row++) {
          //console.log( "Buffer ", buffer[n>>1].toString(16), " base ", base, ' n ', n );
          if( n & 1 )
            card[col][row] = base + ( buffer[n>>1] & 0xF );
          else
            card[col][row] = base + ( buffer[n>>1] >> 4 );
            n++;
        }

      }
    }else{
      var bufData = new ArrayBuffer(buffer.buffer);
      //var buf = new Uint8Array( bufData );
      //console.log( "buf is ", bufData, buffer.data, typeof buffer, Object.getPrototypeOf( buffer ) );
      var card = expand(buffer.slice( 0, 4 ), buffer.slice( 4, 12 ) )
      //console.log( "buf is ", card );
      
    }
    return card;
  }
  if( (buffer.length==8) || ( buffer.length == 7 ) ) {
    // upick 7 or 8 dat buffer
    var card = [];
    buffer.forEach( (val)=>{ card.push(val); })
    return card;
  }
  return undefined;
}

function writeOne( n, card ){
	//var test_buf;
	test_buf = cardUtils.MakeCardFromBuffer( card, 75 );
	var nums = [];
	card = new Uint8Array(card);
	//console.log( "card:", card );
	
	// this sorts the resulting card face array into 'nums' for ordered count 
	// 0 is the N free space.
	for( let c = 0; c < 5; c++ ) for( let r = 0; r < 5; r++ ) {
		for( let n = 0; n < nums.length; n++ ) {
			if( test_buf[c][r] < nums[n] ){
				nums.splice( n, 0, test_buf[c][r] );
				break;
			}
		}
		if( n == nums.length )
			nums.push( test_buf[c][r] );
		
	}

	// previous colum values are now `nums.join(',')`  which is SortCardNumber
	// CardNumber is like `test_buf.map( row=>row.join(",") ).join("," )`
	// CardJson is `JSON.stringify(card)`
	
}