Ayo Alfonso AyoAlfonso

Installing Postgres via Brew

Pre-Reqs

In your command-line run the following commands:

brew doctor
brew update

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

Unit testing react with Jest

What is a unit test?

When given some input, does the output look like x?
Runs quickly

Vanilla JavaScript Quick Reference / Cheatsheet

Just migrated it from Codepen.io to markdown. Credit goes to David Conner.

Working with DOM	Working with JS	Working With Functions
Accessing Dom Elements	Add/Remove Array Item	Add Default Arguments to Function
Grab Children/Parent Node(s)	Add/Remove Object Properties	Throttle/Debounce Functions
Create DOM Elements	Conditionals

	<!DOCTYPE HTML>
	<html lang="en">
	<head>
	<style>
	.dot {
	background-color: red;
	border-radius: 50%;
	width: 20px;
	height: 20px;
	display: block;


	/**
	Using input object type for mutations
	**/
	type Mutation {
	register(input : createPersonInput!):RegisterUserResponse!
	}

	input createPersonInput{
	name: String!

	// Method 1:

	class Parent extends Component {
	state = { foo: '', bar: '', buzz: '' }
	render() {
	return (
	<Child
	setParentState={this.setState}
	>
	)

	import React from 'react';

	export default class CheckboxWithLabel extends React.Component {
	constructor(props) {
	super(props);
	this.state = {isChecked: false};

	// bind manually because React class components don't auto-bind
	// http://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#autobinding
	this.onChange = this.onChange.bind(this);

	/**
	* Retries a function that returns a promise a given number of times and backs
	* off each attempt exponentially.
	*
	* @param {Function} promiseGenerator The function to retry.
	* @param {number} [attempts=5] Number of attempts to make.
	* @param {number} [delay=1000] Initial delay between attempts in ms.
	* @return {Promise}
	*/
	function attemptWithRetry(promiseGenerator, attempts = 5, delay = 100) {

	const response = await fetch(`https://catappapi.herokuapp.com/users/${userId}`)
	const data = await response.json()
	return data.imageUrl
	}