Ytukyg

I'm trying to do a simple notification function
but every time i fire the function i get ERROR

TypeError: Cannot read property 'params' of undefined
at exports.sendNotification.functions.database.ref.onWrite (/user_code/index.js:23:32)
at cloudFunctionNewSignature (/user_code/node_modules/firebase-functions/lib/cloud-functions.js:105:23)
at cloudFunction (/user_code/node_modules/firebase-functions/lib/cloud-functions.js:135:20)
at /var/tmp/worker/worker.js:758:24
at process._tickDomainCallback (internal/process/next_tick.js:135:7)

Or i get the error

TypeError: Cannot read property 'user_id' of undefined

I got an answer from here

but i't didn't help at all , and i can't find the problem . this is my code

'use strict'

const functions = require('firebase-functions');

const admin = require('firebase-admin');

admin.initializeApp();



exports.sendNotification = functions.database.ref('/notifications/{user_id}/{notification_id}').onWrite((change,context) => {



const user_id = event.params.user_id;

const notification_id = event.params.notification_id;



console.log('We have a notification from : ', user_id);



if(!context.data.val()){



return console.log('A Notification has been deleted from the database : ', 

notification_id);



}



const fromUser =admin.database().ref(`/notifications/${user_id}/${notification_id}`).once('value');



return fromUser.then(fromUserResult => {



const from_user_id = fromUserResult.val().from;



console.log('You have new notification from  : ', from_user_id);



const userQuery = admin.database().ref(`Users/${from_user_id}/name`).once('value');

const deviceToken = admin.database().ref(`/Users/${user_id}/device_token`).once('value');



return Promise.all([userQuery, deviceToken]).then(result => {



  const userName = result[0].val();

  const token_id = result[1].val();



  const payload = {

    notification: {

      title : "New Friend Request",

      body: `${userName} has sent you request`,

      icon: "default",

      click_action : "none"

    },

    data : {

      from_user_id : from_user_id

    }

  };



  return admin.messaging().sendToDevice(token_id, payload).then(response => {



    return console.log('This was the notification Feature');



     });



   });



  });



});

You never defined event, so it's undefined. You're trying to access a property on an undefined variable. Did you mean context.params.user_id?

(You're probably using an out of date tutorial. I see bad "sendNotification" functions like this all the time on Stack Overflow. Let the author know.)