nkhil

const AWS = require('aws-sdk')

// a function that returns a promise
function copyFileToS3() {
  
  // initialise AWS S3
  const s3 = new AWS.S3({
    accessKeyId: 'whatever',
    secretAccessKey: 'whatever',
    endpoint: 'http://localhost:4566', // localstack is running on port 4566. Imagine this was the real S3 endpoint

nkhil

const s3 = require('./s3') // This is the file where we use aws-sdk's S3 CopyObject method

const mockS3Instance = {
  copyObject: jest.fn().mockReturnThis(),
  promise: jest.fn().mockReturnThis(),
  catch: jest.fn(),
}

jest.mock('aws-sdk', () => {
  return { S3: jest.fn(() => mockS3Instance) }

nkhil

Calculator

This is my solution to the Calculator kata from CodeWars: https://www.codewars.com/kata/5235c913397cbf2508000048/train/ruby

Kata

Create a simple calculator that given a string of operators (), +, -, *, / and numbers separated by spaces returns the value of that expression

// Example

nkhil

async function someAsyncFuncion(num) {
  return await new Promise(resolve => resolve(num))
}

function orchestrator() {
  [1, 2, 3, 4, 5].forEach(async num => {
    console.log('console 1 fired')
    const promiseResolvedValue = await someAsyncFuncion(num)
    console.log(promiseResolvedValue)
    console.log('console 2 fired')

nkhil

Here's how to create and export an RSA public/private key pair from Node.js

const crypto = require('crypto')
const fs = require('fs')

const { privateKey, publicKey } = crypto.generateKeyPairSync('rsa', {
  modulusLength: 2048,
})

nkhil

const crypto = require('crypto')

const NUMBER_OF_BYTES = 32
const randomBytes = crypto.randomBytes(NUMBER_OF_BYTES)

nkhil

const crypto = require('crypto')
const fs = require('fs')

const { publicKey, privateKey } = crypto.generateKeyPairSync("rsa", {
  // The standard secure default length for RSA keys is 2048 bits
  modulusLength: 2048,
})

// *********************************************************************
//

nkhil

const fs = require('fs')
const crypto = require('crypto')

const dataToEncrypt = fs.readFileSync('data_to_encrypt.txt', { encoding: 'utf-8' })

const publicKey = Buffer.from(fs.readFileSync('public.pem', { encoding: 'utf-8' }))

const encryptedData = crypto.publicEncrypt(
  {
    key: publicKey,

nkhil

const crypto = require('crypto')
const fs = require('fs')

const encryptedData = fs.readFileSync('encrypted_data.txt', { encoding: 'utf-8' })
const privateKey = fs.readFileSync('private.pem', { encoding: 'utf-8' })

const decryptedData = crypto.privateDecrypt(
  {
    key: privateKey,
    // In order to decrypt the data, we need to specify the

nkhil

function parseLogs(logs) {
  const logsArray = logs.split('\n').map(eachLog => eachLog.split(','))
  const normalisedArray = normaliseArray(logsArray)
  const logsWithSeconds = normalisedArray.map(([timestamp, phoneNumber]) =>
    [calculateTotalSeconds(timestamp), phoneNumber])
  const grouped = groupByPhoneNumber(logsWithSeconds)
  const phoneNumberWithLargestTotal = getPhoneNumberWithLargestTotalSeconds(grouped)
  grouped[phoneNumberWithLargestTotal] = 0
  return calculateTotalBill(logsWithSeconds, phoneNumberWithLargestTotal)
}