function processData() {
  try {
    console.log('start');
    throw new Error('oops');
    console.log('after throw');
  } catch (e) {
    console.log('catch');
    return 'caught';
  } finally {
    console.log('finally');
  }
  console.log('end');
}

const result = processData();
console.log(result);

function highlight(strings, ...values) {
  return strings.reduce((result, string, i) => {
    const value = values[i] ? `<mark>${values[i]}</mark>` : '';
    return result + string + value;
  }, '');
}

const name = 'Sarah';
const age = 25;
const template = highlight`Hello ${name}, you are ${age} years old!`;
console.log(template);

const empty = highlight`No interpolation here`;
console.log(empty);

class EventManager {
  constructor() {
    this.listeners = new Map();
  }
  
  addListener(event, callback) {
    if (!this.listeners.has(event)) {
      this.listeners.set(event, new Set());
    }
    this.listeners.get(event).add(callback);
  }
  
  removeListener(event, callback) {
    this.listeners.get(event)?.delete(callback);
  }
}

const manager = new EventManager();
const handler = () => console.log('handled');
manager.addListener('click', handler);
manager.removeListener('click', () => console.log('handled'));
console.log(manager.listeners.get('click').size);