如何使用 firebase 云函数从 firebase-realtime-database 中获取数据？

Question

So I want to fetch data from my firebase realtime database in a firebase cloud function.

My Database structure:

My code:

let usernameFetched: string
const snapshot = await admin.database().ref(`/Agent/${userUID}/username`).once("value")
usernameFetched = snapshot.val().username
console.log(`${usernameFetched}`)

return res.status(200).send({ 
    method: 'sendMessage',
    chat_id,
    text: `Your username is ${usernameFetched}) 
    //This returns a message to user via a telegram bot.
}

I'm using typescript in VSCODE by the way.

The output is always UNDEFINED. Why? The path is correct. I tried all the ways from similar question but didn't helped me.

The function is ASYNC and I have to use the fetched value in other fucntions so I don't want to use return statement here. Any way?

Answer 1

Change this:

usernameFetched = snapshot.val().username

into this:

usernameFetched = snapshot.val()

In your path, you are already using ref(/Agent/${userUID}/username) the username node. Therefore all you have to do to get the value is call .val() on snapshot .