Up & Going Chapter 1

You Don't Know Javascript Yet

Up & Going

Chapter 1 : Into Programming

The best way to learn how to write code is to write code. - Kyle Simpson

Chapter 1 should be approached as a quick overview of the things you'll want to learn more about and practice to get into programming.

(These are some of my notes. Study the chapter on the link below and use this template to make your own notes.This is all still very basic but it is important that you understand each concept fully before moving on to the next chapter. The book series delves deeply into all aspects of JavaScript. If you don't build up a solid foundation of basic understanding you will be overwhelmed and way out of your depth as the series progresses. So take your time to master the basics before moving on.)

Click to view the full text.

prompt ()

age = prompt( "Please tell me your age:" );

alert (`Your age is ${age}`);

String

var amount = 99.99;

amount = amount * 2;

console.log ( amount );

amount = "$" + String( amount );

console.log ( amount );

toFixed ()

var TAX_RATE = 0.08;

var amount = 99.99;

amount = amount * 2;

amount = amount + (amount * TAX_RATE);

console.log( amount );
console.log( amount.toFixed( 2 ) );

const

// as of ES6:
const TAX_RATE = 0.08;

var amount = 99.99;

// ..

if

var bank_balance = 302.13;
var amount = 99.99;

if (amount < bank_balance) {
console.log( "I want to buy this phone!" );
}

else

const ACCESSORY_PRICE = 9.99;

var bank_balance = 302.13;
var amount = 99.99;

amount = amount * 2;

if ( amount < bank_balance ) {
  console.log( "I'll take the accessory!" );
  amount = amount + ACCESSORY_PRICE;
} else {
  console.log( "No, thanks." );
}

while

var numOfCustomers = 1;

while (numOfCustomers > 0) {
  console.log( "How may I help you?" );

  // help the customer...

  numOfCustomers = numOfCustomers - 1;
}

do... while

var numOfCustomers = 1;

do {
  console.log( "How may I help you?" );

  // help the customer...

  numOfCustomers = numOfCustomers - 1;
} while (numOfCustomers > 0);

for

for (var i = 0; i <= 9; i = i + 1) {
console.log( i );
}

function

function printAmount() {
console.log( amount.toFixed( 2 ) );
}

var amount = 99.99;

printAmount();

amount = amount * 2;

printAmount();

function parameters

function printAmount(amt) {
  console.log( amt.toFixed( 2 ) );
}

function formatAmount() {
  return "$" + amount.toFixed( 2 );
}

var amount = 99.99;

printAmount( amount * 2 );

amount = formatAmount();

  console.log( amount );

lexical scope

function one() {
// this `a` only belongs to the `one()` function
  var a = 1;
  console.log( a );
}

function two() {
// this `a` only belongs to the `two()` function
  var a = 2;
  console.log( a );
}

one();
two();

nested scope

function outer() {
  var a = 1;

  function inner() {
     var b = 2;

     // we can access both `a` and `b` here
    console.log( a + b );
  }

   inner();

  // we can only access `a` here
  console.log( a );
}

outer();

YDKJSY Up & Going Chapter 1 (Summary) Now with Run functionality