lib/containers.js
function tryReadBlock(tap) {
  var pos = tap.pos;
  var block = BLOCK_TYPE._read(tap);
  if (!tap.isValid()) {
    tap.pos = pos;
    return null;
  }
  return block;
}
function tryReadBlock(tap) {
  var pos = tap.pos;
  var block = BLOCK_TYPE._read(tap);
  if (!tap.isValid()) {
    tap.pos = pos;
    return null;
  }
  return block;
}
function tryReadBlock ( tap ) { var pos = tap . pos ; var block = BLOCK_TYPE . _read ( tap ) ; if ( ! tap . isValid ( ) ) { tap . pos = pos ; return null ; } return block ; }
Maybe get a block.
Maybe get a block .