Which all industries get affected by AR/VR

Mainly the VR in virtual tour etc. 

Industries use this approach to detect problems early. 

References:

https://www.zdnet.com/video/facebook-forcing-oculus-users-to-have-an-account-on-its-platform/

How do a Hex view of a file

In Mac, the utility is "xxd filename | less"

This shows the data pretty good. something like below 

00000000: 7b0a 2020 226e 616d 6522 3a20 2272 722d  {.  "name": "rr-

00000010: 7265 6163 742d 626f 696c 6572 706c 6174  react-boilerplat

00000020: 6522 2c0a 2020 2276 6572 7369 6f6e 223a  e",.  "version":

If we see that the contents are paired as 4 chars, but each of the 

char is taking two bytes. Just to note.  

References:

https://stackoverflow.com/questions/827326/whats-a-good-hex-editor-viewer-for-the-mac

What is Global In Node JS

Node.js global objects are global in nature and available in all modules. You don't need to include these objects in your application; rather they can be used directly. These objects are modules, functions, strings and object etc. Some of these objects aren't actually in the global scope but in the module scope.

A list of Node.js global objects are given below:

__dirname

__filename

Console

Process

Buffer

setImmediate(callback[, arg][, ...])

setInterval(callback, delay[, arg][, ...])

setTimeout(callback, delay[, arg][, ...])

clearImmediate(immediateObject)

clearInterval(intervalObject)

clearTimeout(timeoutObject)

Node.js __dirname

It is a string. It specifies the name of the directory that currently contains the code.

references:

https://www.javatpoint.com/nodejs-global-objects#:~:text=js%20Global%20Objects-,Node.,functions%2C%20strings%20and%20object%20etc.

How much max bandwidth needed for VoIP?

The bandwidth that our VOIP phone service requires depends on the number of concurrent calls you want to make. The table below shows the minimum bandwidth required to make calls from a Phone.com account, as well as recommended speeds for optimal performance.

Number of Concurrent Calls Minimum Required Bandwidth Recommended speed

1 100 Kbps Up and Down 3 MBps Up and Down

3 300 Kbps Up and Down 3 MBps Up and Down

5 500 Kbps Up and Down 5 MBps Up and Down

10 1 MBps Up and Down 5-10 MBps Up and Down

The answer is simple and complex. VoIP services use a variety of codecs to compress and decompress voice data, allowing it to travel over the Internet efficiently. Phone.com uses codecs that require approximately 100 kilobits per second (kbps) traveling up from your phone line and down to your phone line per second for each call. So if you have three people, all on calls at the same time, the minimum requirement is 300 kbps up and 300 kbps down.

In addition, since the Internet “pipe” into your home or business is being used for other functions too—web browsing, sending and receiving email, file transfers, web-based office services, point-of-sale systems, and so on—there are numerous candidates contending for bandwidth.

How to Determine Your Functional Bandwidth

It helps to know how much bandwidth you really have. However, your Internet Service Provider (ISP) will probably only confirm what you signed up for, also known as the advertised “up to” value, as in “up to 50 Mbps” or “up to 150 Mbps.”

The best way to determine your bandwidth, is to run a throughput test using a site like www.speedtest.net. This will give you a snapshot of your current functional bandwidth, but it is important to note that this metric can vary depending on how much bandwidth all of the different applications you are using require at any given point in time. This test also provides variable results depending on the location used for testing.

Keep in mind that your upload speed is usually slower than your download speed, so you need to make sure that the lower number of the upload speed matches what you need. Since most service providers do not guarantee sustained bandwidth besides the up-to value, we recommend adding a 5x to 10x safety margin when estimating bandwidth.

If you know that your ISP can sustain a certain speed, simply multiply the number of expected concurrent calls by 100 kbps. If you deal with an “up to” ISP, a good solution would be to add the safety margin mentioned above so that you can sustain the required bandwidth, even when your Internet service falters.

For example, 10 concurrent users would require 1 Mbps (10 X 100 kbps x safety margin), which means you would be smart to allow for 5 to 10 Mbps both up and down. Depending on the other services and applications using your Internet connection and on the capabilities of your router, 3 to 5 Mbps may be sufficient, or you may need to increase your bandwidth. This must be evaluated on a case-by-case basis, as each organization is different.

References:

https://www.phone.com/much-bandwidth-need-voip/

How does lets encrypt work?

A nonprofit Certificate Authority providing TLS certificates to 225 million websites

To enable HTTPS on your website, you need to get a certificate (a type of file) from a Certificate Authority (CA). Let’s Encrypt is a CA. In order to get a certificate for your website’s domain from Let’s Encrypt, you have to demonstrate control over the domain. With Let’s Encrypt, you do this using software that uses the ACME protocol which typically runs on your web host.

To figure out what method will work best for you, you will need to know whether you have shell access (also known as SSH access) to your web host. If you manage your website entirely through a control panel like cPanel, Plesk, or WordPress, there’s a good chance you don’t have shell access. You can ask your hosting provider to be sure.

With Shell Access

We recommend that most people with shell access use the Certbot ACME client. It can automate certificate issuance and installation with no downtime. It also has expert modes for people who don’t want autoconfiguration. It’s easy to use, works on many operating systems, and has great documentation. Visit the Certbot site to get customized instructions for your operating system and web server.

If Certbot does not meet your needs, or you’d like to try something else, there are many more ACME clients to choose from. Once you’ve chosen ACME client software, see the documentation for that client to proceed.

If you’re experimenting with different ACME clients, use our staging environment to avoid hitting rate limits.

references:

https://letsencrypt.org/

Material UI Styling

For the sake of simplicity, Material UI expose the styling solution used in Material-UI components as the @material-ui/styles package. You can use it, but you don't have to, since Material-UI is also interoperable with all the other major styling solutions.

n previous versions, Material-UI has used LESS, then a custom inline-style solution to write the component styles, but these approaches have proven to be limited. A CSS-in-JS solution overcomes many of those limitations, and unlocks many great features (theme nesting, dynamic styles, self-support, etc.).

Material-UI's styling solution is inspired by many other styling libraries such as styled-components and emotion.

You can expect the same advantages as styled-components.

🚀 It's blazing fast.

🧩 It's extensible via a plugin API.

⚡️ It uses JSS at its core – a high performance JavaScript to CSS compiler which works at runtime and server-side.

📦 Less than 15 KB gzipped; and no bundle size increase if used alongside Material-UI.

There are 3 possible APIs we can use to generate and apply styles, however they all share the same underlying logic.

Hook API 

=======

import React from 'react';

import { makeStyles } from '@material-ui/core/styles';

import Button from '@material-ui/core/Button';

const useStyles = makeStyles({

  root: {

    background: 'linear-gradient(45deg, #FE6B8B 30%, #FF8E53 90%)',

    border: 0,

    borderRadius: 3,

    boxShadow: '0 3px 5px 2px rgba(255, 105, 135, .3)',

    color: 'white',

    height: 48,

    padding: '0 30px',

  },

});

export default function Hook() {

  const classes = useStyles();

  return <Button className={classes.root}>Hook</Button>;

}

Styled components API

=====================

Note: this only applies to the calling syntax – style definitions still use a JSS object. You can also change this behavior, with some limitations.

import React from 'react';

import { styled } from '@material-ui/core/styles';

import Button from '@material-ui/core/Button';

const MyButton = styled(Button)({

  background: 'linear-gradient(45deg, #FE6B8B 30%, #FF8E53 90%)',

  border: 0,

  borderRadius: 3,

  boxShadow: '0 3px 5px 2px rgba(255, 105, 135, .3)',

  color: 'white',

  height: 48,

  padding: '0 30px',

});

export default function StyledComponents() {

  return <MyButton>Styled Components</MyButton>;

}

Higher-order component API

==========================

import React from 'react';

import PropTypes from 'prop-types';

import { withStyles } from '@material-ui/core/styles';

import Button from '@material-ui/core/Button';

const styles = {

  root: {

    background: 'linear-gradient(45deg, #FE6B8B 30%, #FF8E53 90%)',

    border: 0,

    borderRadius: 3,

    boxShadow: '0 3px 5px 2px rgba(255, 105, 135, .3)',

    color: 'white',

    height: 48,

    padding: '0 30px',

  },

};

function HigherOrderComponent(props) {

  const { classes } = props;

  return <Button className={classes.root}>Higher-order component</Button>;

}

HigherOrderComponent.propTypes = {

  classes: PropTypes.object.isRequired,

};

export default withStyles(styles)(HigherOrderComponent);

References:

https://material-ui.com/styles/basics/

What is Higher order component ?

A higher-order component (HOC) is an advanced technique in React for reusing component logic. HOCs are not part of the React API, per se. They are a pattern that emerges from React’s compositional nature.

Concretely, a higher-order component is a function that takes a component and returns a new component.

const EnhancedComponent = higherOrderComponent(WrappedComponent);

Whereas a component transforms props into UI, a higher-order component transforms a component into another component.

HOCs are common in third-party React libraries, such as Redux’s connect and Relay’s createFragmentContainer.

Components are the primary unit of code reuse in React. However, you’ll find that some patterns aren’t a straightforward fit for traditional components.

For example, say you have a CommentList component that subscribes to an external data source to render a list of comments:

References:

https://reactjs.org/docs/higher-order-components.html#:~:text=A%20higher%2Dorder%20component%20(HOC,React%20for%20reusing%20component%20logic.&text=They%20are%20a%20pattern%20that,and%20returns%20a%20new%20component.