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Nodemailer: Uncaught TypeError: Class extends value undefined is not a constructor or null

Im trying to use nodemailer to send an email from a contact form. Below is all my code relating to nodemailer aswell as a screenshot of the error I get.
import nodemailer from 'nodemailer';
let transporter = nodemailer.createTransport({
host: 'smtppro.zoho.com',
port: 465,
secure: true,
auth: {
user: '',
pass: '',
},
});
const date = new Date(Date.now());
let contact = await transporter.sendMail({
from: `"${this.data.name}" <${this.data.email}>`,
to: this.data.staff,
subject: `Contact Page Submission: ${this.data.subject}`,
html: `
<h1>New Contact Form Submission</h1>
<span><b>From:</b> ${this.data.name} - ${this.data.email}</span><br>
<span><b>Subject:</b> ${this.data.subject}</span><br>
<span><b>To:</b> ${this.data.staff}</span><br>
<span><b>Sent At:</b> ${date.toUTCString()}</span><br><br>
<span><b>Message:</b></span>
<p>${this.data.message}</p>
`,
});
When I try to load the page it throws the exception. When I remove the import statement it loads just like normal. This is all contained inside of a Vue.JS project. I have the latest version of nodemailer installed.

nodemailer runs only in Node. The screenshot shows you're trying to
use it from the browser, which won't work
-- #tony19

Trying connection mqtt in browser

I'm trying to get a mqtt connection on my browser with JS
I'm following this tutorial: https://emqx.medium.com/use-websocket-to-connect-to-mqtt-broker-9e7baf1aa773
So I've got this:
<script src="https://unpkg.com/mqtt/dist/mqtt.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/paho-mqtt/1.0.1/mqttws31.js" type="text/javascript"></script>
<script>
// Globally initializes an mqtt variable
const clientId = 'mqttjs_' + Math.random().toString(16).substr(2, 8)
const host = 'ws://broker.***.***.com:9883'
const options = {
keepalive: 60,
clientId: clientId,
username: '***',
password: '***',
protocolId: 'MQTT',
protocolVersion: 4,
clean: true,
reconnectPeriod: 1000,
connectTimeout: 30 * 1000,
will: {
topic: 'WillMsg',
payload: 'Connection Closed abnormally..!',
qos: 0,
retain: false
},
}
console.log('Connecting mqtt client')
const client = mqtt.connect(host, options)
client.on('connect', () => {
console.log('Client connected:' + clientId)
// Subscribe
})
</script>
And in my browser I've got this error:
After some research, some people say that need to use certificate: https://github.com/eclipse/paho.mqtt.javascript/issues/187
So, I've got this :
<script src="../browserMqtt.js"></script>
<script src="https://unpkg.com/mqtt/dist/mqtt.min.js"></script>
<script>
var options = {
keyPath: '../credentials/client-key.pem',
certPath: '../credentials/client-cert.pem',
rejectUnauthorized : false,
ca: ['../credentials/a-cert.pem'],
protocolId: 'MQTT',
username: '***',
password: '***',
clientId: 'mqttjs_' + Math.random().toString(16).substr(2, 8)
};
var client = mqtt.connect('ws://broker.***.***.com:9883',options);
client.on('connect', function(){
console.log('Connected');
});
</script>
I've got the same error in browser ...
The broker conguration for mosquitto, it's like this :
allow_anonymous false
password_file /mosquitto/config/passwd
#TCP
listener 1883
socket_domain ipv4
#SSL
listener 8883
socket_domain ipv4
cafile /mosquitto/config/tls/ca/ca-cert.pem
certfile /mosquitto/config/tls/server/server-cert.pem
keyfile /mosquitto/config/tls/server/server-key.pem
tls_version tlsv1.2
socket_domain ipv4
#WSS
listener 9883
socket_domain ipv4
protocol websockets
cafile /mosquitto/config/tls/ca/ca-cert.pem
certfile /mosquitto/config/tls/server/server-cert.pem
keyfile /mosquitto/config/tls/server/server-key.pem
tls_version tlsv1.2
persistence true
persistence_location /mosquitto/data/
log_dest file /mosquitto/log/mosquitto.log
log_timestamp_format %Y-%m-%dT%H:%M:%S
log_type all
I can't understand how can I solve it ? Thanks for your help

You can't use client side certs in the browser to authenticate the client (unless you load them into the browsers keystore, but even then I'm not convinced it will work unless there is only one cert/key for the browser to pick as javascript code won't normally prompt the user to pick the right one).
Also loading client certs over http from the server totally defeats the point of using a client cert as anybody can download them.
You need to remove all of the following from the options
keyPath: '../credentials/client-key.pem',
certPath: '../credentials/client-cert.pem',
rejectUnauthorized : false,
ca: ['../credentials/a-cert.pem'],
protocolId: 'MQTT',
Because the paths are meaningless in the browser (and for the reasons I mentioned earlier)
You should also be starting your broker URL with wss:// to make it clear you are trying to connect over secure WebSockets.

How to create an offline MySQL database javascript?

I have created a sample.js file with the following code
var mysql = require('mysql');
Typically, I would connect to my online database using:
var pool = mysql.createPool({
host: 'den1.mysql5.gear.host',
user: 'myst',
password: 'hidden',
database: "myst"
});
and then do
var connection = pool.getConnection(function(err, connection) {
//do whatever like connection.query
});
How can I create a local database file and access that, instead of using server side databases?
Edit: USING ONLY MySQL!
If you do not know, please do not answer. I am not looking for an alternative (since most alternatives cause node to delete packages needed by discord.js for some reason).

MySQL is quite heavy to implement database on front end as there is size and speed limitations. I'll prefer using it on back end only but if you want to use database on front-end you can use db.js. There is indexDB presently present in most of the modern browser. The db.js is a wrapper around that consumes it to implement database on front end. Here's sample provided on the documentation.
<script src='/scripts/db.js'></script>
var server;
db.open( {
server: 'my-app',
version: 1,
schema: {
people: {
key: { keyPath: 'id' , autoIncrement: true },
// Optionally add indexes
indexes: {
firstName: { },
answer: { unique: true }
}
}
}
} ).done( function ( s ) {
server = s
} );

Apply Sqlite/Any SQL Database Migrations with Electron [Windows, Mac]

My Scenario,
I am working on a desktop based application. Where My big challenge is keeping data into relational DB(Offline) and sync accordingly(Company have their own syncing algorithm). I am using Electron and VueJS as client side. For building the desktop app I'm using electron-builder. I am able to write migrations with raw SQL or various ORM.
What I want?
While I'll install into a desktop, I want to create the database file and apply all the migrations on the client's computer. I just don't know that part how to do that. I also looked into Electron Builder Docs. But didn't understand. I need an example, any idea.
Please help me. Thanks

After doing a lot of research I found an awesome solution provided by sequalize.js. I found a library Umzug Github. Let's look at the implementation...
/**
* Created by Ashraful Islam
*/
const path = require('path');
const Umzug = require('umzug');
const database = /* Imported my database config here */;
const umzug = new Umzug({
storage: 'sequelize',
storageOptions: {
sequelize: database
},
// see: https://github.com/sequelize/umzug/issues/17
migrations: {
params: [
database.getQueryInterface(), // queryInterface
database.constructor, // DataTypes
function () {
throw new Error('Migration tried to use old style "done" callback. Please upgrade to "umzug" and return a promise instead.');
}
],
path: './migrations',
pattern: /\.js$/
},
logging: function () {
console.log.apply(null, arguments);
}
});
function logUmzugEvent(eventName) {
return function (name, migration) {
console.log(`${name} ${eventName}`);
}
}
function runMigrations() {
return umzug.up();
}
umzug.on('migrating', logUmzugEvent('migrating'));
umzug.on('migrated', logUmzugEvent('migrated'));
umzug.on('reverting', logUmzugEvent('reverting'));
umzug.on('reverted', logUmzugEvent('reverted'));
module.exports = {
migrate: runMigrations
};
Idea behind the scene
I clearly declare the migration directory. Also, define the file matching pattern. Umzug just read files from there and run the DB migration. An example migration file is following...
// 000_Initial.js
"use strict";
module.exports = {
up: function(migration, DataTypes) {
return migration.createTable('Sessions', {
sid: {
type: DataTypes.STRING,
allowNull: false
},
data: {
type: DataTypes.STRING,
allowNull: false
},
createdAt: {
type: DataTypes.DATE
},
updatedAt: {
type: DataTypes.DATE
}
}).then(function() {
return migration.addIndex('Sessions', ['sid']);
});
},
down: function(migration, DataTypes) {
return migration.dropTable('Sessions');
}
};

how can i set the dns of the node js server?

I want to set the primary dns , secondary dns of node js server.
But i use 'setup' module , there are only dns , not secondary dns.
Like this
var setup = require('setup')();
var config = setup.network.config({
wlan0: {
auto: true, // start at Boot
dhcp: true, // Use DHCP
wireless: {
ssid: 'myWirelessName', // Wireless SSID
psk: 'mySuperPassword', // Password
}
},
eth0: {
auto: true,
ipv4: {
address: '192.168.1.20',
netmask: '255.255.255.0',
gateway: '192.168.1.1',
dns: '8.8.8.8'
}
}
});
how can i set primary dns and secondary dns of the node js?
I would appreciate your help.