Software Dev Weekly Update #11: Современные возможности JavaScript

const numbers = [9, 8, 7, 6, 5, 4, 3, 2, 1];

//We are passing an in-line function, though we could define a
//function outside of the forEach and instead plug in the 
//function name
numbers.forEach(function(n){
    console.log(n * n)
    //Prints: 81, 64, 49, 36, 25, 16, 9, 4, 1
});

const movies = [
    {
        title: ""Toy Story","
        score: 92
    },
    {
        title: ""Stand By Me","
        score: 85
    },
    {
        title: ""Soul","
        score: 95
    },
    {
        title: ""Avengers: End Game","
        score: 94
    },
    {
        title: ""Finding Nemo","
        score: 86
    },
];

//Creates a new array called "titles" pulling from the movies array
const titles = movies.map(function(movie){
    return movie.title;
})

//setTimeout-----------------------------------------------
//runs and prints 1st
console.log("Hello!")

//This will run just one time, and will print 3rd
setTimeout(function(){
    console.log("I waited 3 seconds...");
}, 3000)

//this runs 3rd but will print out 2nd because setTimeout is on a
//3 second delay
console.log("Last coded console.log message!")


//setInterval-----------------------------------------------
//Using an arrow function this time, doesn't matter but is shorter
//Will run forever every two seconds
//We set this to a variable so we can call clearInterval(id)
const id = setInterval(() =>{
    console.log(Math.random());
}, 2000)

const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
const odds = numbers.filter(n => {
    return n % 2 === 1;
    //Our callback returns true or false, if true n is added to the filtered array
})
//Will return [1, 3, 5, 7, 9]

const smallNumbers = numbers.filter(n => n < 5);
//will return [1, 2, 3, 4]

[3, 5, 7, 9, 11].reduce((accumulator, currentValue) =>{
    return accumulator + currentValue;
});
//The final return value for this will be 35

//We've set this function's default params so that if the user
//doesn't input a value when calling rollDie() then it will
//use 6 as the default for numSides
function rollDie(numSides = 6){
    return Math.floor(Math.random() * numSides) +1;
}

const nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];

//To use Math.max we need to "spread" the array of numbers into individual values so the function can find the maximum value
//We use ... before calling the nums array to "spread" the values inside the nums array
//Spread creates the seperate arguments (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) from the nums array and then 
//executes the .max() function with those arguments
console.log(`The maximum number is: ${Math.max(...nums)}`);

const cats = ["Ella", "Tommy", "Buddy"];
const dogs = ["Daisy", "Piston"];

//We are spreading the two arrays into a new array
const allPets = [...cats, ...dogs];
console.log(allPets);

//A real world example, a user signs up for our website and we want to copy their input and add data of our own
const dataFromform = {
    email: "fake@gmail.com",
    username: "SirFaketon",
    password: "fakepassword123"
}

//Now lets add data to their input
const newUser = {...dataFromform, id: 12345, isAdmin: false}

function raceResults(gold, silver, ...everyoneElse){
    console.log(`Gold medal goes to: ${gold}`);
    console.log(`Silver medal goes to: ${silver}`);
    console.log(`And thanks to everyone else for participating: ${everyoneElse}`);

console.log(raceResults("Ethan", "Dan", "Tim", "Ashley"));
}

const pinballScores = [984537, 912385, 872357, 817490, 817245, 726349, 613279];

//With this we are making 3 variables (gold, silver, and bronze)
//and the order of the array determines what values they are
//Gold will be index 0, silver will be index 1, and bronze will be index 2
//The [] indicate we are destructing from an array
//Also we are using the ... or "rest" parameter to define the rest of the scores
const [gold, silver, bronze, ...everyoneElse] = pinballScores;

console.log(`Gold score is: ${gold}`);
console.log(`Silver score is: ${silver}`);
console.log(`Bronze score is: ${bronze}`);
console.log(`Runner up scores are: ${everyoneElse}`);

//An exmaple of destructing an object
const runner = {
    firstName: "Eliud",
    lastName: "Kipchoge",
    country: "Kenya",
    title: "Elder of the Order of the Golden Heart of Kenya"
}
const {firstName, lastName, country} = runner;

console.log(`The winner of the race is ${firstName} ${lastName} from ${country}!`);

const user1 = {
    email: "stacy@gmail.com",
    firstName: "Stacy",
    lastName: "LaPreaze",
    born: 1975,
    city: "Morley",
    state: "Michigan"
}

const user2 = {
    email: "george@gmail.com",
    firstName: "George",
    lastName: "Windfall",
    born: 1935,
    died: 1987,
    city: "Morley",
    state: "Michigan",
    occupation: "Systems Engineer"
}

//Destructure and only grab firstName and lastName. Also setting a
//default value (param) in case there's no info, but this is
//totally optional
function fullName({firstName = "Missing Value", lastName = "Missing Value"}){
    return `${firstName} ${lastName}`;
}