Pirates

'use strict';

//I basically should've just used a class and defined the methods (commands) on each new town object. I started off with a different solution and had to hack/tweak it to fit my needs so I don't have to refactor the whole thing. I'm setting the 2 methods directly on the town containing object so later on I'm subtracting them from the keys' length so I can print the right amount of towns. I also have a conditional to check if any of the objects' keys are functions and not printing them at the end.
//PS: The commented out sort doesn't work in ALL of the cases. Use the working one from now on.

function pirates(arr) {
  const cityStats = {};

  //Loop through targeted cities
  let line;
  while ((line = arr.shift()) !== 'Sail') {
    //Split data from input
    let [town, population, gold] = line.split('||');
    //Convert to numbers
    [population, gold] = [population, gold].map(Number);

    //If town is already present, just add to existing values
    if (cityStats.hasOwnProperty(town)) {
      cityStats[town].population += population;
      cityStats[town].gold += gold;
    } else {
      //Create new values
      cityStats[town] = {
        population,
        gold,
      };
    }
  }

  //Add methods to the obj
  cityStats['Plunder'] = plunder;
  cityStats['Prosper'] = prosper;

  //Loop through events
  while ((line = arr.shift()) !== 'End') {
    //Split data from events
    let [command, ...args] = line.split('=>');

    //Execute command
    cityStats[command](args);

    //Check if town is to be disbanded
    let town = args[0];
    let deadTown =
      cityStats[town].gold === 0 || cityStats[town].population === 0;

    if (deadTown) {
      delete cityStats[town];
      console.log(`${town} has been wiped off the map!`);
    }
  }

  //Sort
  // .sort((townA, townB) => townA.localeCompare(townB))
  // .sort((townA, townB) => cityStats[townB].gold - cityStats[townA].gold);
  let sortedKeys = Object.keys(cityStats).sort((townA, townB) => {
    if (cityStats[townB].gold - cityStats[townA].gold === 0) {
      return townA.localeCompare(townB);
    } else {
      return cityStats[townB].gold - cityStats[townA].gold;
    }
  });

  let keysLength = sortedKeys.length - 2 < 0 ? 0 : sortedKeys.length - 2;

  //Output
  console.log(
    `Ahoy, Captain! There are ${keysLength} wealthy settlements to go to:`
  );

  sortedKeys.forEach((town) => {
    if (typeof cityStats[town] !== 'function') {
      console.log(
        `${town} -> Population: ${cityStats[town].population} citizens, Gold: ${cityStats[town].gold} kg`
      );
    }
  });

  //Declarations
  function plunder(params) {
    let [town, population, gold] = params;
    [population, gold] = [population, gold].map(Number);

    //Subtract plundered gold and killed population
    cityStats[town].population -= population;
    cityStats[town].gold -= gold;

    console.log(
      `${town} plundered! ${gold} gold stolen, ${population} citizens killed.`
    );
  }

  function prosper(params) {
    let [town, gold] = params;
    gold = Number(gold);

    if (gold < 0) {
      console.log('Gold added cannot be a negative number!');
      return;
    }

    //If the gold value is not a negative number add to treasury
    cityStats[town].gold += gold;
    //Print
    console.log(
      `${gold} gold added to the city treasury. ${town} now has ${cityStats[town].gold} gold.`
    );
  }
}

let result = pirates([
  'Nassau||95000||1000',
  'San Juan||930000||1250',
  'Campeche||270000||690',
  'Port Royal||320000||1000',
  'Port Royal||100000||2000',
  'Sail',
  'Prosper=>Port Royal=>-200',
  'Plunder=>Nassau=>94000=>750',
  'Plunder=>Nassau=>1000=>150',
  'Plunder=>Campeche=>150000=>690',
  'End',
]);
console.log(result);