bluethoot low energy and bangle js2

I try to ram my code in my watch with espruino ide but when i connected to nrfconnect to see the service i try to install nothing appear.

// Fonction pour initialiser les services BLE
function initBLE() {
  NRF.setServices({
    0x180A: { // UUID du service Device Information
      0x2A56: { // UUID de la caractéristique pour écrire
        value: [0x00], // Valeur initiale
        maxLen: 20,    // Taille maximale des données
        writable: true, // Autoriser l'écriture
        onWrite: function(evt) {
          let data = evt.data;
          console.log("Données reçues : ", data);
          require("Storage").write("config", data);
        }
      },
      0x2A57: { // UUID de la caractéristique pour lire
        value: [0x00], // Valeur initiale
        maxLen: 20,    // Taille maximale des données
        readable: true, // Autoriser la lecture
        onRead: function() {
          let data = require("Storage").read("config") || [0x00];
          console.log("Données lues : ", data);
          return data;
        }
      }
    }
  }, { advertise: ['0x180A'] });

  console.log("Bluetooth prêt et services configurés");
}

// Redémarrer le Bluetooth pour s'assurer qu'il est correctement initialisé
NRF.restart(function() {
  console.log("Bluetooth redémarré");
  initBLE();
});

you should not do the initialization of services inside NRF.restart(), that's meant for code that runs while bluetooth stack is completely disabled

https://www.espruino.com/Reference#l_NRF_restart

callback - [optional] A function to be called while the softdevice is uninitialised. Use with caution - accessing console/bluetooth will almost certainly result in a crash.

you managed to actually do both things advised not to do :-)

As @fanoush says - don't use NRF.restart. Just call initBLE directly.

NRF.restart is really a very low level function, pretty much nobody should ever need to call in normal use.