在节点js上使用BLENO无法使BLE特性出现在主服务中

Question

I have a simple app shown below. I have created a primary service and added characteristics to my service using BLENO on node js on Rpi3.

It seems that my app starts and runs ok. I have used two tools to view my BLE service ie Nordic nRF application and a simple app I wrote in Android.

Using these apps I can see my BLE app advertising and i can also connect to it. When connected I can see three services which are two generic and one being my "unknown service" which has matching UUID as i have set in my BLE server app.

The problem I am having is when I expend my service, it tells me there are no characteristics set for my service.

I would appreciate if someone could review the code below and check possible reason for no characteristics appearing in my service.

`var bleno = require("bleno");
var BlenoPrimaryService = bleno.PrimaryService;
var Characteristic = bleno.Characteristic;
var Descriptor = bleno.Descriptor;
//var UserConfigCharecteristic = require('./user-config-characteristic');

bleno.on('stateChange', function (state) {
    console.log('on -> stateChagne: ' + state);
    if (state === 'poweredOn') {
        console.log('ble has been powered on');
        bleno.startAdvertising('rpi-ble-app', ['fffffffffffffffffffffffffffffff0']);
    } else {
        bleno.stopAdvertising();
    }
});

bleno.on('advertisingStart', function () {
console.log('-> advertising start');
bleno.setServices([
    new BlenoPrimaryService(
            {
                uuid: 'fffffffffffffffffffffffffffffff0',
                charecteristics: [
                    new Characteristic({
                        uuid: 'fffffffffffffffffffffffffffffff1', // or 'fff1' for 16-bit
                        properties: ['read', 'write'], // can be a combination of 'read', 'write', 'writeWithoutResponse', 'notify', 'indicate'
                        secure: [], // enable security for properties, can be a combination of 'read', 'write', 'writeWithoutResponse', 'notify', 'indicate'
                        value: null, // optional static value, must be of type Buffer - for read only characteristics
                        descriptors: [],
                        onReadRequest: null, // optional read request handler, function(offset, callback) { ... }
                        onWriteRequest: null, // optional write request handler, function(data, offset, withoutResponse, callback) { ...}
                        onSubscribe: null, // optional notify/indicate subscribe handler, function(maxValueSize, updateValueCallback) { ...}
                        onUnsubscribe: null, // optional notify/indicate unsubscribe handler, function() { ...}
                        onNotify: null, // optional notify sent handler, function() { ...}
                        onIndicate: null // optional indicate confirmation received handler, function() { ...}
                    })
                ]
            }
    )], function (error) {
    console.log('setServices: ' + (error ? 'error ' + error : 'success'));
});

});

bleno.on('servicesSet', function () {
    console.log('services set.');
});`

Output for my node.js app is

on -> stateChagne: poweredOn
ble has been powered on
-> advertising start
services set.
setServices: success

Answer 1

Check this one. https://github.com/sandeepmistry/bleno/issues/301 . However, my problem was that services were not visible.

Answer 2

Seems I have found the problem, I had misspelled Characteristics.

I'm new to nodejs and realise that mis-spelling can be an issue since if you mis-spell you wont override instead you will add a new property.