Wait an event to resolve a promise

Question

I am using a node.js module that has a method without callbacks. Instead of it, has an event that fires when that method has finished. I want resolve a promise, using that event as callback securing me that method has been completed succesfully.

array.lenght on promise can be X. So, I need 'hear' X times the event to secure me that all methods has completed succesfully <-- This is not the problem, I am just telling you that I know this could happen

Event :

tf2.on('craftingComplete', function(recipe, itemsGained){
  if(recipe == -1){
  console.log('CRAFT FAILED')
  }
  else{
        countOfCraft++;
    console.log('Craft completed! Got a new Item  #'+itemsGained);
  }
})

Promise:

const craftWepsByClass = function(array, heroClass){
        return new Promise(function (resolve, reject){

            if(array.length < 2){
                console.log('Done crafting weps of '+heroClass);
                return resolve();
            }
            else{
                for (var i = 0; i < array.length; i+=2) {
                    tf2.craft([array[i].id, array[i+1].id]); // <--- this is the module method witouth callback
                }
        return resolve(); // <---- I want resolve this, when all tf2.craft() has been completed. I need 'hear' event many times as array.length
            }   

        })
}

Answer 1

At first lets promisify the crafting:

function craft(elem){
 //do whatever
 return Promise((resolve,reject) => 
  tf2.on('craftingComplete', (recipe,itemsGained) => 
   if( recipe !== -1 ){
     resolve(recipe, itemsGained);
   }else{
    reject("unsuccessful");
   }
  })
);
}

So to craft multiples then, we map our array to promises and use Promise.all:

Promise.all( array.map( craft ) )
 .then(_=>"all done!")