greathmaster

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?

greathmaster

{
	"version": "0.2.0",
	"configurations": [
	  {
		  "type": "node",
		  "request": "launch",
		  "name": "Mocha All",
		  "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
		  "args": [
			  "--timeout",

greathmaster

function Dog(name, breed) {
	this.name = name;
	this.breed = breed;
}

Dog.prototype.sayHello = function(sound1, sound2) {
	console.log(`The dog ${this.name}, a ${this.breed}, says Hello! And makes sounds ${sound1} and ${sound2}`)
}

function Cat(name, breed) {

greathmaster

//Example 1:
Function.prototype.secretCurry = function() {
	let secret = "password"
	let that = this;
	return function inner(guess) {
		if(guess == secret) {
			that();
		}
		return inner;
	 }

greathmaster

Array.prototype.myEach = function(callback) {
	for (let i = 0; i < this.length; i++) {
		callback(this[i]);
	}
}

Array.prototype.myMap = function(callback) {
	let newArray = []
	const collect = function(el) {
		newArray.push(callback(el))

greathmaster

# Controller	Plural	
rails g controller Users index show

# Helper	Plural	
rails g helper Users

# Mailer	Singular	
rails g mailer UserMailer

# Migration	Plural	

greathmaster

#Ruby string references clarification
#Mutation of a string
x = "Hello"
y = x
x << " WORLD" #changing the underlying item in memory
puts x  #Hello WORLD
puts y  #Hello WORLD

a = "Hello"
b = a

greathmaster

#Lazy evaluation in Ruby
@menu || = ["cookies", "bananas", "water"]

#The above is syntatic sugar for
@menu = @menu || ["cookies", "bananas", "water"] 

#Similar concept to
x = x + 10	#Both are the same, but different snytax
x += 10

greathmaster

//Fetch with Promises and explicit functions

	fetch('https://jsonplaceholder.typicode.com/posts/1')
	.then(function (res) { return res.json()})
	.then(function (data) {
	
		//Make use of the data variable here
    	console.log(data)
	  })
	  

greathmaster

function func() {
  let promise = fetch('https://api.github.com/zen')
  return promise.then((successResponse) => {
    console.log(successResponse)
    return successResponse.text();
  })
}

func().then((resp) => {console.log(resp)})