I'm having trouble understanding how to reference and read wildcard node that has value.

RTDB (Can I have a sample path reference?):

What I've done :

     //  Define your RTDB Reference
    const rtdbReference = admin.database().ref("Sensor MQ7");
    const mq7ref = rtdbReference.child("-NHi7dBPMlVi6hXrnI03");
    const valref = mq7ref.child("MQ7");

    //  Fetch the data
    const snap = await valref.get();
    const snapValue = snap.val();

   //  Inject snapvalue in the response
   return res.status(200).send({
      method: "sendMessage",
      chat_id,
      text: `${first_name}\n${receivedMessage}\n${snapValue}`,
    });

The output : Eg

How do I make it so that it reads any wildcard node and output everything. Right now it only reads individual node when I specify it. Please help because I've been going at this since morning now its 10pm and if possible please explain like I'm 5 because I'm really really new to this.

CodePudding user response：

To read and log all nodes under Sensor MQ7, you can do:

const reference = admin.database().ref("Sensor MQ7");

const snapshot = await reference.get();

snapshot.forEach((childSnapshot) => {
    console.log(childSnapshot.child("MQ7").val());
});

In here:

• snapshot contains a snapshot of all data under the Sensor MQ7 nodes.
• snapshot.forEach() loops over the child nodes of the snapshot.
• child("MQ7") then gets the snapshot for that specific property.
• .val() gets its value.