Proposed node-pre-gyp plugin for checking ALPN compatibility in Node

node-pre-gyp-alpn-check-plugin.js

exports.checkVersion = function(callback) {

  var TEST_KEY = "-----Insert TLS private key-----";

  var TEST_CERT = "------Insert TLS certificate-----";

  var tls = require('tls');

  var server = tls.createServer({key: TEST_KEY, cert:TEST_CERT, ALPNProtocols: ['h2']});

  server.listen(0, 'localhost', function() {
    var port = server.address().port;
    var connect_options = {host: 'localhost',
                           port: port,
                           rejectUnauthorized: false,
                           ALPNProtocols: ['h2']};
    var tlsSocket = tls.connect(connect_options, function() {
      if (tlsSocket.alpnProtocol === 'h2') {
        callback({tls: 'alpn'});
      } else {
        callback({tls: 'npn'});
      }
      tlsSocket.end();
      server.close();
    });
  });
}