spcheema

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

spcheema

/**
 * Return current date object according to given timezone. Date will be return based on system's timezone an error occured while parsing
 *
 * @param timezone Timezone string e.g. `America/Los_Angeles`
 * @returns {Date}
 */
function currentDate(timezone) {
    try {
        return new Date(new Date().toLocaleString("en-US", {timeZone: timezone}));
    } catch (error) {

spcheema

    /**
     * Replaces any parameter placeholders in a query with the value of that
     * parameter. Useful for debugging. Assumes anonymous parameters from
     * $params are are in the same order as specified in $query
     *
     * @param string $query The sql query with parameter placeholders
     * @param array $params The array of substitution parameters
     * @return string The interpolated query
     *
     * @link https://stackoverflow.com/questions/210564/getting-raw-sql-query-string-from-pdo-prepared-statements

spcheema

Get started with React & Babel

A Pen by Surinder pal Singh on CodePen.

License.

spcheema

through2 = require 'through2'


module.exports = ->
  words = 0
  lines = 1
  transform = (chunk, encoding, cb) ->

    # Count lines
    if chunk.match(/\n/mg)

spcheema

fs = require 'fs'

exports.countryIpCounter = (countryCode, cb) ->
  return cb() unless countryCode

  fs.readFile "#{__dirname}/../data/geo.txt", 'utf8', (err, data) ->
    if err then return cb err
    counter = 0
    data = data.toString()