JS Concepts

function createGreeter(greeting) {
  return function (name) {
    console.log(greeting + ", " + name);
  };
}

const sayHello = createGreeter("Hello");
sayHello("Joe"); // Hello, Joe
sayHello("Mihail"); // Hello, Mihail
sayHello("Chris"); // Hello, Chris

console.log(sayHello);

// Spread Syntax
const arr = [4, 6, -1, 3, 10, 4];
const max = Math.max(...arr);
console.log(max);

// Rest Syntax
function myFunc(...args) {
  console.log(args[0] + args[1]);
}

myFunc(1, 2, 3, 4);

// Callback Functions
function myLogger(arg) {
  console.log(arg);
}
function myFuncCb(text, callback) {
  setTimeout(function () {
    callback(text);
  }, 300);
}

myFuncCb("Hello world!", myLogger);

// Promises
const myPromise = new Promise(function (res, rej) {
  setTimeout(function () {
    if (Math.random() < 0.9) {
      return res("Hooray!");
    }
    return rej("Oh no!");
  }, 1000);
});

myPromise
  .then(function (data) {
    console.log("Success: " + data);
  })
  .catch(function (err) {
    console.log("Error: " + err);
  });

// Async Await
const greeterPromise = new Promise((res, rej) => {
  setTimeout(() => res("Hello Mihail!"), 250);
});

async function myFuncAsync() {
  const greeting = await greeterPromise;
  console.log(greeting);
}

myFuncAsync(); // 'Hello world!'