CODEWITHSUNDEEP
javascriptarrayslodash
Ceddy Muhoza
Ceddy Muhoza

Reputation: 636

Javascript Iterate over chunk/grouped array

Am in a situation, where i have an array with thousands of items, first i break this array into groups of chunks 1000 per each, then i call a function which processes the first chunk in the array and it returns the new grouped chunks.

// Using lodash
var array = []; // my array with many items
var ids = _.chunk(array, 1000); // grouped array 1000 each

function LoopArrayGroups(ids){

  var arrSize = _.size(ids); // number of groups

  if(arrSize != 0){
    // get First group array,remove it from the list
    var toBeUsed = ids[0];
    ids.splice(0, 1);

    //process first group 
    myFunction(toBeUsed, function(promise){

      if(!promise.error){

        // return new array with the first group removed
        return ids;

      }else{
        console.log("Some error " + promise.error);
      }

    });

  }
}

The LoopArrayGroups method is called with an array of grouped chunks then it processes the first chunk, removes it then returns new grouped chunks ,

I just want to loop through the group arrays until they become empty. instead of calling this function over and over again

Upvotes: 1

Views: 1324

Answers (1)

trincot
trincot

Reputation: 350310

Instead of:

return ids;

call the main function again:

LoopArrayGroups(ids);

Remark

The recursive call will increase the use of the stack on each call on most environments, because currently not many JavaScript engines have implemented the tail-recursion optimisation.

Practically this means that if you have a huge amount of chuncks, you could run into stack overflow errors. If this is a concern, you should alter the recursive call to make it asynchronous:

setTimeout(LoopArrayGroups.bind(ids), 0);

As you already have asynchronous processing in myFunction, there is in fact no downside in doing it this way.

Upvotes: 4

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