Chalarangelo

// An array of objects.
var myFriends = [
  { name: "John", surname: "Smith", age: 52},  
  { name: "Sarah", surname: "Smith", age: 49},  
  { name: "Michael", surname: "Jones", age: 46},  
  { name: "Garry", surname: "Thomas", age: 48}
];

// A simple function to get just the name and
// surname in one string.

Chalarangelo

// An array of high scores. Notice that some
// of them don't have a name specified.
var highScores = [
  {score: 237, name: "Jim"},
  {score: 108, name: "Kit"},
  {score: 91, name: "Rob"},
  {score: 0},
  {score: 0}
];

Chalarangelo

// An array of people.
var myFriends = [
  { name: "John", gender: "male" },
  { name: "Kate", gender: "female" },
  { name: "Mike", gender: "male" },
  { name: "Sophie", gender: "female" },
  { name: "Richard", gender: "male" },
  { name: "Keith", gender: "male" }
];

Chalarangelo

// Definition of our comparison function.
var sortByWeight = function(x,y){
  var xW = x.measurement == "kg" ? x.weight : x.weight * 0.453592;
  var yW = y.measurement == "kg" ? y.weight : y.weight * 0.453592;
  return xW > yW ? 1 : -1;
}

// Just two slightly different lists of data,
// that need to be sorted based on weight.
var firstList = [

Chalarangelo

// Create a function.
function f(x){
  return x * x;
}
// Use the function.
f(5); // 25

// Create an anonymous function and assign 
// it to a variable.
var g = function(x){

Chalarangelo

function user(username, password){
  // Here we use closures to define public functions
  // that can access private variables.
  return {
    getUsername() { return username; },
    setUsername(newUsername) {username = newUsername; },
    checkPassword(givenPassword) { return password == givenPassword; }
  }
}

Chalarangelo

function someFunction(){
  if (true){
    // This variable is defined inside these
    // curly braces, which means its part of the
    // scope of this block and cannot be accessed
    // by other parts of someFunction.
    let blockVariable = 30;
    
    // However, using the 'var' keyword this variable,
    // while defined inside the same block, is part of

Chalarangelo

// This is a function and it defines its own
// local scope. argumentVariable is part of the
// function's scope, as it is an argument in its
// definition.
function parentFunction(argumentVariable){
  // functionVariable and anotherVariable are both
  // part of parentFunction's local scope.
  var functionVariable = 10;
  let anotherVariable = 15;
  

Chalarangelo

// This variable is part of the global scope
var globalVariable = 10;

function someFunction(){
  // globalVariable is accessible from someFunction,
  // as it is part of the global scope
  console.log(globalVariable);
}

someFunction(); // Prints 10

Chalarangelo

if ('serviceWorker' in navigator) {
  navigator.serviceWorker
    .register('./service-worker.js')
    .then(function() { console.log('Registered service worker!'); });
}