old_contents: const http = require('http');
  const fs   = require('fs');
  
  const port = Number( process.argv[2] );
  const file = process.argv[3];
  if ( isNaN(port) || undefined === file ) {
      // bail immediately
      return;
  }
  
  http.createServer( function( _, response ) {
      const rs = fs.createReadStream( file );
      rs.on('open', function() {
          rs.pipe( response );
      });
      rs.on('error', function(err) {
          console.error('Could not find ' + file + ', sorry');
          return;
      });
  }).listen( port );
  
new_contents: const http = require('http');
  const fs   = require('fs');
  
  const port = Number( process.argv[2] );
  const file = process.argv[3];
  if ( isNaN(port) || undefined === file ) {
      // bail immediately
      return;
  }
  
  http.createServer( function( _, response ) {
      const rs = fs.createReadStream( file );
      rs.on('open', function() {
          rs.pipe( response );
      });
      rs.on('error', function() {
          console.error('Could not read ' + file + ', sorry');
          return;
      });
  }).listen( port );
  
subject: Remove unused variable