Javascript async in nested for loop MongoDB

Question

I have an asynchronous function inside a for loop nested in another for loop.

// recipesArray is an array of arrays of objects
// recipeObject is an array of objects
// currentRecipe is an object

connectToDb(function(){
   // LOOP 1
   for (var i=0, l=recipesArray.length; i < l; i++) {
      // recipeObject is an 
      var recipeObject = recipesArray[i];

      // LOOP 2
      for (var x=0, y=recipeObject.length; x < y; x++) {
         var currentRecipe = recipeObject[x];

         // this is an asynchronous function
         checkRecipe(currentRecipe, function (theRecipe) {
            if (theRecipe === undefined) {
               console.log('RECIPE NOT FOUND');
            } else {
               console.log('RECIPE FOUND', theRecipe);
            }
         });
      }
   }
});

I need to add data to the recipesArray based on the results of the checkRecipe function.

I've been trying different things... - do i try to keep track of i and x... - do i try to have multiple callbacks... - do i even need to do all of that, or is there some other way....

I also tried using the async library for node(which actually has been very helpful with other situations), but the forEach doesn't take objects(only an array).

Stuck.

Any suggestions would be greatly appreciated.

Answer 1

Assuming checkRecipe() can be run in parallel with no limits, here's how you might use async.each():

connectToDb(function() {
  async.each(recipesArray, function(subArray, callback) {
    async.each(subArray, function(currentRecipe, callback2) {
      checkRecipe(currentRecipe, function(theRecipe) {
        if (theRecipe === undefined)
          return callback2(new Error('Recipe not found'));
        callback2();
      });
    }, callback);
  }, function(err) {
    if (err)
      return console.error('Error: ' + err);

    // success, all recipes found
  });
});