Combining nests

When downloading a large amount of data, it can be necessary to do reduction at various stages in order to not have to hold all of the data at once.

In this block I would like to nest the data using d3's nest function, and then add additional objects to the nest as they come in.

<!DOCTYPE html>
<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no"/>
<style>

</style>
<body ng-app>
	<table id="chart"></table>
</body>
<script src="//d3js.org/d3.v4.min.js"></script>
<script>
  
  // *** Any of the object attributes can be included in here
  var nestOrder = ["faveColor","drives", "birthMonth"];
 
  // *** Helper function to create nests dynamically
	function createNestingFunction(propertyName){
  	return function(d){ 
  		return d[propertyName];
  	};
	}
  
  // *** Create nesting function
	var nest = d3.nest();
  for (var i = 0; i < nestOrder.length; i++) {
    nest = nest.key( createNestingFunction(nestOrder[i]) );
  }
  
  // *** Open files and process
  d3.queue()
  .defer(d3.json, "dataSet1.json")
  .defer(d3.json, "dataSet2.json")
  .await(function(error, dataSet1, dataSet2) {
		if (error) throw error;
   
    // *** Create nest for dataSet1
    var valuesSet1 = nest.entries(dataSet1);
    
    // *** Create nest for dataSet2
    var valuesSet2 = nest.entries(dataSet2);
    
    
    var newNest = [];
  	joinNests(valuesSet1, newNest);
  	joinNests(valuesSet2, newNest);
    
    console.log('Finished: ');
  	console.log(newNest);
  });

// *** Helper function to combine nests
  // *** Pass in a nest and a nest that is being combined into. Created 
  // *** in this was so that dynamic numbers of nests can be added
  function joinNests(nest1, newNest){
    
    if(nest1.length <= 0){
      return;
    }

for(var i in nest1){
      var found = false;
      
      for(var j in newNest){
				if(nest1[i].hasOwnProperty('values') 
        && nest1[i]['key'] == newNest[j]['key']){
          found = true;
          
          if(nest1[i].hasOwnProperty('values')){
            joinNests(nest1[i]['values'],newNest[j]['values']);
          }
        }
      }
      
      if(found == false){
        newNest.push(nest1[i]);
      }
      
    }
    
  }

</script>

https://d3js.org/d3.v4.min.js