Javascript - Back From Break

Leon Noel

#100Devs

 

 I be getting money 'til I fall out
You talking cash, dog, I goes all out
 

Agenda

  • Questions? 

  • Let's Talk -  Coming Up?

  • Let's Talk -  #100Devs

  • Review - The BIG FOUR

  • Review - Arrays

  • Review - Objects

  • Review - Basic APIs

  • Homework - OOP

Questions

About last class or life

This Week

Review 

OOP

Next Week

OOP Practice

Async / Await

THEN BACKEND

Checking In

Like and Retweet the Tweet

!checkin

Catching up on Discord

Gonna Get Funky

No Networking Until May

Client Deadline: May 5th

Client Alternatives

Grassroots Volunteer*

Free Software / Open Source

https://www.firsttimersonly.com/

!youtube

!newsletter

Discord Update

Private LGBTQ+ channel

Live Crafting Your Story

FRIDAY
6:30pm EST

OFFICE HOURS

SUNDAY
1:00pm EST

Enough for a job?

Yes

HUGE ANNOUNCEMENT NEXT WEEK

Programming

What is a program?

A program is a set of instructions that you write to tell a computer what to do

What is a programming?

Programming is the task of writing those instructions in a language that the computer can understand.

JAVASCRIPT

Variables

Declaration: let age

 

Assignment: age = 25

 

Both at the same time:

let age = 25

Conditional Syntax

if(condition is true) {
  //Do this cool stuff
}else if(condition is true){
  //Do this other cool stuff
}else{
  //Default cool stuff
}

Multiple Conditions

if (name === "Leon" && status === "Ballin"){
 //Wink at camera
}

Multiple Conditions

if (day === "Saturday" || day === "Sunday"){
  //It is the weekend
}

Functions

What are functions?

Functions

  • Functions are simple sets of instructions!

  • Functions are reusable

  • Functions perform one action as a best practice

  • They form the basic "building blocks" of a program

Functions

function name(parameters){
  //body
}

//call
name(arguments)

Functions

function yell(word){
  alert(word)
}


yell("HELLO")

Loops

What are loops?

Loops

  • Repeat an action some number of times!

  • Three main types of loops in Javascript

  • For, while, and do while loops

  • Each type offers a different way to determine the start and end points of a loop

Loops - For

for (let i = 1; i < 5; i++) {
  console.log(i)
}

Let's Code

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Arrays

What are arrays?

Toasters

Arrays

  • A data structure to store ordered collections!

  • Array elements are numbered starting with zero

  • Arrays have many methods to manage the order of elements

  • Can be created by a constructor or literal notation

Declaring Arrays

let newArr = []

Literal Notation

Declaring Arrays

newArr = ['Zebra',true,21]

Arrays are populated with elements

Elements can be of any type

Array Indexing

Array Indexing

newArr = ['Zebra',,true,21]

console.log( newArr[0] )  //Zebra
console.log( newArr[1] )  //undefined
console.log( newArr[2] )  //true
console.log( newArr[3] )  //21

Elements can be accessed by their index numbers

Array Indexing

newArr = ['Zebra',,true,21]

newArr[1] = 'Bob'

console.log( newArr )  

// ['Zebra','Bob',true,21]

Elements can be updated by using the index at that position

Array Length

console.log( newArr.length ) //4

How do you determine how many elements are in your array?

Array Iteration

let bestColors = ['green','blue','yellow','black']

bestColors.forEach((x,i)=> console.log(x))

Iterates through an array passing in the value and index of each element 

Let's Code

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Objects

What are objects?

Objects

  • Objects are a collection of variables and functions!

  • Objects represent the attributes and behavior of something used in a program

  • Object variables are called properties and object functions are called methods

  • Objects store "keyed" collections

Think of a physical object

What are it's attributes and behaviors? 

How about a stopwatch

What are its attributes (properties) and behaviors (methods)? 

Stopwatch Object

let stopwatch = {}

stopwatch.currentTime = 12

stopwatch.tellTime = function(time){
  console.log(`The current time is ${time}.`)
}

stopwatch.tellTime(stopwatch.currentTime)

Objects

What if we want to make

a lot of objects?

How much money you got? How many problems you got? How many people done doubted you? Left you out to rot?

Car Factory?

Constructors then Classes

Car Factory

Constructor

function MakeCar(carMake,carModel,carColor,numOfDoors){
  this.make = carMake
  this.model = carModel
  this.color = carColor
  this.doors = numOfDoors
  this.honk = function(){
    alert('BEEP BEEP FUCKER')
  }
  this.lock = function(){
    alert(`Locked ${this.doors} doors!`)
  }
}

let hondaCivic = new MakeCar('Honda','Civic','Silver', 4)

let teslaRoadster = new MakeCar('Tesla','Roadster', 'Red', 2)

Car Factory

We forgot enable bluetooth! 

let teslaRoadster = new MakeCar('Tesla','Roadster', 'Red', 2)

console.log( teslaRoadster.bluetooth )  //undefined

MakeCar.prototype.bluetooth = true

console.log( teslaRoadster.bluetooth ) //true

A prototype is another object that is used as a fallback source of properties

Car Factory

Why does .toString() work?!?

let teslaRoadster = new MakeCar('Tesla','Roadster', 'Red', 2)

console.log( teslaRoadster.doors.toString() )  // "2" not 2

A prototype is another object that is used as a fallback source of properties

Car Factory

Look Ma! New syntax!

class MakeCar{
  constructor(carMake,carModel,carColor,numOfDoors){
    this.make = carMake
    this.model = carModel
    this.color = carColor
    this.doors = numOfDoors
  }
  honk(){
    alert('BEEP BEEP FUCKER')
  }
  lock(){
    alert(`Locked ${this.doors} doors!`)
  }
}

let hondaCivic = new MakeCar('Honda','Civic','Silver', 4)

let teslaRoadster = new MakeCar('Tesla','Roadster', 'Red', 2)

Classes are like templates for objects!

Let's Code

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APIs

What are APIs?

APIs

  • A simple interface for some complex action!

  • Think of a restaurant menu! Remember those...

  • Lets one thing communicate with another thing without having to know how things are implemented.

APIs

APIs

Fetch Fido, Fetch!

fetch("https://dog.ceo/api/breeds/image/random")
    .then(res => res.json()) // parse response as JSON
    .then(data => {
      console.log(data)
    })
    .catch(err => {
        console.log(`error ${err}`)
    });

API returns a JSON object that we can use within our apps

APIs

Stop trying to make Fetch happen!

fetch(url)
    .then(res => res.json()) // parse response as JSON
    .then(data => {
      console.log(data)
    })
    .catch(err => {
        console.log(`error ${err}`)
    });

Some APIs need Query Parameters to return the correct data

const url = 'https://www.thecocktaildb.com/api/json/v1/1/search.php?s=margarita'

Let's Code

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Homework

 

Do: Something With The Pokemon API (Thursday)

Watch / Do: https://youtu.be/PFmuCDHHpwk

Read / Do: JS Way Ch. 09

Push? Read / Do: Eloquent JS Ch. 06

Do: 7 Codewars

#100Devs - Javascript Review - Back From Break

By Leon Noel

#100Devs - Javascript Review - Back From Break

Class 29 of our Free Web Dev Bootcamp for folx affected by the pandemic. Join live T/Th 6:30pm ET leonnoel.com/twitch and ask questions here: leonnoel.com/discord

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