The Universalfunction library exported as Node.js modules.

Installation Using npm:

$ npm i  universalfunction

// Load the full build.

var universalfunction = require('universalfunction');

//Documentation

//Sending notification to users //installation

$ npm install fcm-node

//Usage

const FCM = require('fcm-node');
const serverKey = 'YOURSERVERKEYHERE'; //put your server key here
const fcm = new FCM(serverKey);

const message = { //this may vary according to the message type (single recipient, multicast, topic, et cetera)
    to: 'registration_token', 
    collapse_key: 'your_collapse_key',
    
    notification: {
        title: 'Title of your push notification', 
        body: 'Body of your push notification' 
    },
    
    data: {  //you can send only notification or only data(or include both)
        my_key: 'my value',
        my_another_key: 'my another value'
    }
};

fcm.send(message, function(err, response){
    if (err) {
        console.log("Something has gone wrong!");
    } else {
        console.log("Successfully sent with response: ", response);
    }
});

//Authentication with passport

//Installation

$ npm i passport

//load passport

const passport = require('passport')

isAuthenticated()  //checks whether user authenticated or not

//usage

checkAuthenticate=(req,res,next)=> {
    if(req.isAuthenticated()){
        return next()
    }else{
        return res.send('login first')
    }
}//If user is authenticated(logged in) then passes to the next else returns back to login page

// for generating randon bytes with crypto

//Installation

$ npm i crypto

//load crypto

const crypto = require('crypto');


crypto.randomBytes(Number,callback)//creates the random bytes

//usage

tokenGenrator= (done)=>{
    crypto.randomBytes(2,(err,buf)=>{
    let token = buf.toString('hex');
    done(err,token)
})
}  //4a22
//Number=2 and this then this number is converted into hexadecimal string

//Sending mail to the user with nodemailer //installation

$ npm i nodemailer

//load nodemailer

const nodemailer = require("nodemailer")

//usage

const nodemailer = require('nodemailer');

// create reusable transporter object using the default SMTP transport
var transporter = nodemailer.createTransport('smtps://user%40gmail.com:[email protected]');

// setup e-mail data with unicode symbols
var mailOptions = {
    from: '"" <[email protected]>', // sender address
    to: '[email protected], [email protected]', // list of receivers
    subject: 'Hello ', // Subject line
    text: 'Hello world ', // plaintext body
};

// send mail with defined transport object
transporter.sendMail(mailOptions, function(error, info){
    if(error){
        return console.log(error);
    }
    console.log('Message sent: ' + info.response);
});

//Database Queries

//Get Users from DB

getData = (criteria, projection, options, callback) =>{
    Model.find(criteria, projection, options, callback);
};

//Insert User in DB

create = (objToSave, callback)=> {
    new Models(objToSave).save(callback)
};

//Update User in DB

//For updating one entry
findAndUpdate = (criteria, dataToSet, options, callback)=> {
    Model.findOneAndUpdate(criteria, dataToSet, options, callback);
};

//for Updating multiple enteries
updateMultiple = (criteria, dataToSet, options, callback) =>{
    Model.update(criteria, dataToSet, options, callback);
};

// Populate from db

getPopulate = (criteria, project, options,populateArray, callback)=> {
    Model.find(criteria, project, options).populate(populateArray).exec(function (err, docs) {
        if (err) {
            return callback(err, docs);
        }else{
            callback(null, docs);
        }
    });
};

// delete entry from db

// for deleting the single entry
deleteData=(criteria,callback)=>{
    Model.deleteOne(criteria,callback)
}

// for deleting the multiple entries
deleteData=(criteria,callback)=>{
    Model.deleteMany(criteria,callback)
}