enums.js

const TRUCK = 1;

function getCarByType(type) {
  if (type === TRUCK) {
    return { name: 'Super Truck' }; // imagine that it's a truck object
  } 
  return { name: 'Usual Car' };
}

enums2.js

const TRUCK = 1;
const SEDAN = 2;

function getCarByType(type) {
  if (type === TRUCK) {
    return { name: 'Super Truck' }; // imagine that it's a truck object
  }
  
  if (type === SEDAN) {
    return { name: 'Starry Sedan' }; // imagine that it's a sedan object
  }
  
  return { name: 'Usual Car' };
}

enums3.js

const ProcessStatuses = {
  STARTED: 1,
  IN_PROGRESS: 2,
  FINISHED: 3
}

enums4.js

const ProcessStatuses = Object.freeze({ 
  STARTED: 1, 
  IN_PROGRESS: 2, 
  FINISHED: 3 
});

enums5.js

class ProcessStatuses {
  static STARTED = new ProcessStatuses('STARTED', 1);
  static IN_PROGRESS = new ProcessStatuses('IN_PROGRESS', 2);
  static FINISHED = new ProcessStatuses('FINISHED', 3);
  
  constructor(key, value) {
    this.key = key;
    this.value = value;
    // here you can include more different properties
    Object.freeze(this);
  }
  
  // toString is just an example of some custom logic that can be implemented here
  toString() {
    return `[${this.key}]${this.value}`;
  }
}