exlorer.js

/**
 * Demo peripheral/devices explorer
 * Credits https://github.com/noble/noble/blob/master/examples/peripheral-explorer.js
 */
const async = require('async');

module.exports = function explore(peripheral) {
  console.log('services and characteristics:');

  // peripheral.on('disconnect', function() {
  //   process.exit(0);
  // });

  peripheral.connect(function (error) {
    if (error) return error;

    peripheral.discoverServices([], function (error, services) {
      if (error) return error;

      var serviceIndex = 0;

      async.whilst(
        function () {
          return serviceIndex < services.length;
        },
        function (callback) {
          var service = services[serviceIndex];
          var serviceInfo = service.uuid;

          if (service.name) {
            serviceInfo += ' (' + service.name + ')';
          }
          console.log(serviceInfo);

          service.discoverCharacteristics([], function (error, characteristics) {
            var characteristicIndex = 0;

            async.whilst(
              function () {
                return characteristicIndex < characteristics.length;
              },
              function (callback) {
                var characteristic = characteristics[characteristicIndex];
                var characteristicInfo = '  ' + characteristic.uuid;

                if (characteristic.name) {
                  characteristicInfo += ' (' + characteristic.name + ')';
                }

                async.series([
                  function (callback) {
                    characteristic.discoverDescriptors(function (
                      error,
                      descriptors
                    ) {
                      async.detect(
                        descriptors,
                        function (descriptor, callback) {
                          if (descriptor.uuid === '2901') {
                            return callback(descriptor);
                          } else {
                            return callback();
                          }
                        },
                        function (userDescriptionDescriptor) {
                          if (userDescriptionDescriptor) {
                            userDescriptionDescriptor.readValue(function (
                              error,
                              data
                            ) {
                              if (data) {
                                characteristicInfo +=
                                  ' (' + data.toString() + ')';
                              }
                              callback();
                            });
                          } else {
                            callback();
                          }
                        }
                      );
                    });
                  },
                  function (callback) {
                    characteristicInfo +=
                      '\n    properties  ' +
                      characteristic.properties.join(', ');

                    if (characteristic.properties.indexOf('read') !== -1) {
                      characteristic.read(function (error, data) {
                        if (data) {
                          var string = data.toString('ascii');

                          characteristicInfo +=
                            '\n    value       ' +
                            data.toString('hex') +
                            " | '" +
                            string +
                            "'";
                        }
                        callback();
                      });
                    } else {
                      callback();
                    }
                  },
                  function () {
                    console.log(characteristicInfo);
                    characteristicIndex++;
                    callback();
                  }
                ]);
              },
              function (error) {
                serviceIndex++;
                callback();
              }
            );
          });
        },
        function (err) {
          peripheral.disconnect();
        }
      );
    });
  });
};