onurinanc

function getLuckyNumber(){
  
  const userInput = prompt("Enter your lucky number");
  const parsedValue = parseInt(userInput);
  
  if(isNan(parsedValue) || parsedValue <=0){
    throw { message: "Invalid user input"};
  }
  return parsedValue;
}

onurinanc

class Error {
  constructor(message) {
    this.message = message;
    this.name = "Error";
    this.stack = <call stack>;
  }
}

onurinanc

class ValidationError extends Error {
  constructor(message) {
    super(message);
    this.name = "ValidationError";
  }
}

onurinanc

class PropertyRequiredError extends ValidationError {
  constructor(property) {
    super("No property: " + property);
    this.name = "PropertyRequiredError";
    this.property = property;
   }
}

onurinanc

try {
  luckyNumber = getLuckyNumber();
} catch(error){
  console.log(error);
  luckyNumber = Math.floor(Math.random() * 101);
  alert("You entered something wrong, a random value will be used.");
}

onurinanc

function createCar(json) {
  let car = JSON.parse(json);
  
  if (!car.age) {
  throw new PropertyRequiredError("age");
  }
  if (!car.color) {
  throw new PropertyRequiredError("color");
  }
  if (!car.brandName) {

onurinanc

try {
  let car = createCar ('{ "color": black-yellow}');
} catch (err) {
  if (err instanceof ValidationError) {
  alert("Invalid data: " + err.message);
  alert(err.name); // PropertyRequiredError
  alert(err.property); // name
} else {
  throw err;
}

onurinanc

let pipeline = [increment, double, decrement];

const result = pipeline.reduce(function(total, func) {
  return func(total);
}, 8);

// result: 17

onurinanc

const apples = ['green', 'red', 'red', 'yellow', 'red', 'yellow', 'green', 'green'];

var appleMap = apples.reduce((prev, apple) => {
  if (prev[apple] >= 1) prev[apple]++;
  else prev[apple] = 1;
  return prev;
}, {});

console.log(appleMap);
// result: {green: 3, red: 3, yellow: 2}

onurinanc

const apples = ['green', 'red', 'red', 'yellow', 'red', 'yellow', 'green', 'green'];

var appleMap = apples.reduce((prev, apple) => {
  if (prev[apple] >= 1) prev[apple]++;
  else prev[apple] = 1;
  return prev;
}, {});

console.log(appleMap);
// result: {green: 3, red: 3, yellow: 2}