Code 1-13.js

let powerOn=() => {
  if(!ship.powerOn)ship.powerOn=true;
}; 
let countModules=() =>{
  return availableModules.length;
};

let countEssential=() =>{
  return availableModules.filter(function(module){
    return module.essential;
  } ).length;
};

let loadModule=(index,essential)=>{
  if(index<0)throw new Error("Index must be positive");
  let modCount=countModules();
  if(index>modCount)throw new Error("Index must wthin 0 and " +modCount);
  let module=availableModules[index];
  module.enabled=true;
  if(essential!==undefined)module.essential=essential;
  ship.modules.push(module);
};

let findModuleIndex=(moduleName) =>{
  return availableModules.findIndex(function(module){
    return module.name==moduleName;
  });
};

let loadModuleByName=(name,essential)=>{
  loadModule(findModuleIndex(name,essential));
};
let resetLARRY=()=>{
  for(let i=0; i<10;i++)LARRY.quack();
};
let setMessage=(message)=>{
  radio.message=message;
};
let activateBeacon=()=>{
  radio.beacon=true;
};
let setFrequency=()=>{
    let range=radio.range;
    radio.frequency=(range.low+range.high)/2;
};
let initialize=()=>{
  navigation.x=0;
  navigation.y=0;
  navigation.z=0;
};
let calibrateX=()=>{
  for(let i=1; i<=12;i++){
    let signal=checkSignal();
    if(signal!==undefined){
      navigation.x=signal;
      break;
    }
  }
};
loadModuleByName("life-support");
loadModuleByName("propulsion",true);
loadModuleByName("navigation",true);
loadModuleByName("communication",true);
resetLARRY();
setMessage(JSON.stringify(navigation));
activateBeacon();
calibrateX();