ESLint error while trying to deploy firebase functions

I tried deploying a firebase functions but it keeps failing due to some issue with ESLint. I have also tried googling the answer but everything I am seeing is all Greek to me.

I have also stumbled on this and this answer but it appears they're not applicable to my scenario.

My Function

// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
// exports.helloWorld = functions.https.onRequest((request, response) => {
//  response.send("Hello from Firebase!");
// });


//import firebase functions modules
const functions = require("firebase-functions");
//import admin module
const admin = require("firebase-admin");
admin.initializeApp(functions.config().firebase);

// Listens for new messages added to messages/:pushId
exports.pushNotification = functions.database.ref("/Message").onWrite( event => {
    //  Grab the current value of what was written to the Realtime Database.
    var valueObject = event.data.val();
    // Log the event
    console.log("Push notification event triggered for " + valueObject.title);

    //if(valueObject.title != null) {
      //valueObject.photoUrl= "Sent you a photo!";
   // }

  // Create a notification
    const payload = {
        data: {
            body:valueObject.body,
            imgUrl: valueObject.imgUrl,
            postUrl: valueObject.postUrl,
            title: valueObject.title
        },
    };

  //Create an options object that contains the time to live for the notification and the priority
    const options = {
        priority: "high",
        timeToLive: 60 * 60 * 24
    };


    return admin.messaging().sendToTopic("Posts", payload, options);
});

Log

0 info it worked if it ends with ok
1 verbose cli [ '/home/xoxo/.nvm/versions/node/v9.5.0/bin/node',
1 verbose cli   '/home/xoxo/.nvm/versions/node/v9.5.0/bin/npm',
1 verbose cli   '--prefix',
1 verbose cli   '/home/xoxo/Android/Projects/FirebaseFunctions/functions',
1 verbose cli   'run',
1 verbose cli   'lint' ]
2 info using npm@5.6.0
3 info using node@v9.5.0
4 verbose run-script [ 'prelint', 'lint', 'postlint' ]
5 info lifecycle functions@~prelint: functions@
6 info lifecycle functions@~lint: functions@
7 verbose lifecycle functions@~lint: unsafe-perm in lifecycle true
8 verbose lifecycle functions@~lint: PATH: /home/xoxo/.nvm/versions/node/v9.5.0/lib/node_modules/npm/node_modules/npm-lifecycle/node-gyp-bin:/home/xoxo/Android/Projects/FirebaseFunctions/functions/node_modules/.bin:/home/xoxo/.nvm/versions/node/v9.5.0/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
9 verbose lifecycle functions@~lint: CWD: /home/xoxo/Android/Projects/FirebaseFunctions/functions
10 silly lifecycle functions@~lint: Args: [ '-c', 'eslint .' ]
11 info lifecycle functions@~lint: Failed to exec lint script
12 verbose stack Error: functions@ lint: `eslint .`
12 verbose stack spawn ENOENT
12 verbose stack     at ChildProcess.<anonymous> (/home/xoxo/.nvm/versions/node/v9.5.0/lib/node_modules/npm/node_modules/npm-lifecycle/lib/spawn.js:48:18)
12 verbose stack     at ChildProcess.emit (events.js:160:13)
12 verbose stack     at maybeClose (internal/child_process.js:943:16)
12 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:220:5)
13 verbose pkgid functions@
14 verbose cwd /home/xoxo/Android/Projects/FirebaseFunctions
15 verbose Linux 4.13.0-32-generic
16 verbose argv "/home/xoxo/.nvm/versions/node/v9.5.0/bin/node" "/home/xoxo/.nvm/versions/node/v9.5.0/bin/npm" "--prefix" "/home/xoxo/Android/Projects/FirebaseFunctions/functions" "run" "lint"
17 verbose node v9.5.0
18 verbose npm  v5.6.0
19 error file sh
20 error code ELIFECYCLE
21 error errno ENOENT
22 error syscall spawn
23 error functions@ lint: `eslint .`
23 error spawn ENOENT
24 error Failed at the functions@ lint script.
24 error This is probably not a problem with npm. There is likely additional logging output above.
25 verbose exit [ 1, true ]

Console Output

xoxo@xo9:~/Android/Projects/FirebaseFunctions$ firebase deploy

=== Deploying to 'testproject-a1bda'...

i  deploying functions
Running command: npm --prefix $RESOURCE_DIR run lint

> functions@ lint /home/xoxo/Android/Projects/FirebaseFunctions/functions
> eslint .

sh: 1: eslint: not found
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn
npm ERR! functions@ lint: `eslint .`
npm ERR! spawn ENOENT
npm ERR! 
npm ERR! Failed at the functions@ lint script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/xoxo/.npm/_logs/2018-02-03T22_35_55_608Z-debug.log

Error: functions predeploy error: Command terminated with non-zero exit code1

Package.js

{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "scripts": {
    "lint": "./node_modules/.bin/eslint .",
    "serve": "firebase serve --only functions",
    "shell": "firebase experimental:functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "dependencies": {
    "firebase-admin": "~5.8.1",
    "firebase-functions": "^0.8.1"
  },
  "devDependencies": {
    "eslint": "^4.12.0",
    "eslint-plugin-promise": "^3.6.0"
  },
  "private": true
}

Please what am I doing wrong?

The only way I can imagine that your project got into this state is if you refused to allow npm to install dependencies at the time of project creation. So when you asks you this:

? Do you want to install dependencies with npm now?

You may have answered 'No'. This would prevent the eslint package from being installed, and you would see that error.

Otherwise, you may have deleted the eslint installed package under node_modules somehow. You can run npm install from the functions folder to recreate everything needed under node_modules.