Javascript Fundamentals: Associative Arrays - Armies

function solve(params) {
  let armies = {};
  let armyLeaders = [];

  for (let param of params) {
    if (param.includes("arrives")) {
      let indexOfArrives = param.indexOf("arrives");
      let leader = param.slice(0, indexOfArrives).trim();
      if (!armies.hasOwnProperty(leader)) {
        armies[leader] = {
          armiesName: {},
          totalArmyCount: 0
        };
      }
      armyLeaders.push(leader);
    } else if (param.includes("defeated")) {
      let indexOfDefeated = param.indexOf("defeated");
      let leader = param.slice(0, indexOfDefeated).trim();
      let indexOfLeader = armyLeaders.indexOf(leader);
      if (armies.hasOwnProperty(leader)) {
        delete armies[leader];
        armyLeaders.splice(indexOfLeader, 1);
      }
    } else if (param.includes(":")) {
      let [leader, army] = param.split(": ");
      let [armyName, armyCount] = army.split(", ");
      if (armies.hasOwnProperty(leader)) {
        if (!armies[leader].armiesName.hasOwnProperty(armyName)) {
          armies[leader].armiesName[armyName] = Number(armyCount);
          armies[leader].totalArmyCount += Number(armyCount);
        }
      }
    } else if (param.includes("+")) {
      let [armyName, armyCount] = param.split(" + ");
      armyLeaders.forEach(leader => {
        for (let army in armies[leader]) {
          if (armies[leader][army].hasOwnProperty(armyName)) {
            armies[leader].armiesName[armyName] += Number(armyCount);
            armies[leader].totalArmyCount += Number(armyCount);
          }
        }
      });
    }
  }

  Object.entries(armies)
    .sort((a, b) => b[1].totalArmyCount - a[1].totalArmyCount)
    .forEach(army => {
      console.log(`${army[0]}: ${army[1].totalArmyCount}`);
      Object.values(army[1]).forEach(armyInfo =>
        Object.entries(armyInfo).forEach(a =>
          console.log(`>>> ${a[0]} - ${a[1]}`)
        )
      );
    });
}