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Cheat Sheet: Datastructures and Algorithms

By Ira Herman

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Big O Notation:

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React Router

By Alex Merced Updates by Ira Herman

Learning Objectives

• Use React Router's BrowserRouter, Link, Route, Redirect, and Switch

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"Take-Home" Coding Challenge: Movies App

By Ira Herman

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This code challange prompt is modeled after real-world take-home code challenges/prompts many companies use as part of their technical interview process.

This will help you practice/prepare to build a mini-project off of specs, and give you practice/reinforcement using ReactJS with an API back end.

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How to access your MongoDB in a command-line node shell using mongoose

To load up a node console where you can access the database:

in terminal, run node then paste in these lines:

require("dotenv").config();
// Connect to mongodb:
require("./config/database");
// Load up our models:

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Run Server:

python3 manage.py runserver

Create DB:

createdb

Make migrations:

python3 manage.py makemigrations

Migrate DB:

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Classroom Culture

How to succeed in class:

• Take initiative.
• Ask for help.
• Practice, practice, practice.

Let's all agree to:

• Treat each other with respect
• Avoid bringing distractions into class

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RESTful Routes to CRUD Mapping

Example resource: fruits

In I.N.D.U.C.E.S. route order:

URL	HTTP Verb	Action	Notes
/fruits/	GET	index	INDEX when a user types localhost:3000/fruits in browser this route shows a list or index of all fruits
/fruits/new	GET	new	NEW when a user types localhost:3000/fruits/new in browser this route shows the user a form to create a NEW fruit

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Git Workflow CheatSheet

By Ira Herman

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Use this workflow when working with teams to take advantage of Pull Requests and keep the master branch clean.

Creating and using your own branch locally:

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Hooks: useState

Learning Objectives:

• Explain what hooks do and how they let us use function components instead of class components.
• Work with tuples.
• Practice converting stateful class components to functional components with the useState hook.

🔗Codesandbox Demo

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React Hooks

Intro to Hooks

Hooks were introduced in React Version 16.8.

Before hooks, all state needed to be within a Class component. Class components come with a lot of boilerplate, which can feel bulky, especially when dealing with a simpler state. Function components, on the other hand, are generally simpler and easier to read - but, until recently, could not manage their own state: they would receive some props, and return some JSX based on those props.

Hooks introduce state management to Function components, using a simpler and more flexible API. Here's an example of a Class component refactored to be a Function component with hooks: