faster mr for picsio

gistfile1.txt

var query = { user: ObjectId("54ef43552e90860000000001"), trashed: { $ne: true } }; 

function map(){
        if(this.tags && this.tags.length) {
            var emits = []; // store all future emits. we will unique it later
            for(var i=0; i<this.tags.length;i++){
                
                var tag = this.tags[i];
                var path = tag.path;
                while(path.length){
                    emits[path] = 1; // no need to count similar tags twice
                    var lastDelimiter = path.lastIndexOf('/');
                    path = path.slice(0, lastDelimiter);
                }
            }
            // emit accumulate keys
            for(var k in emits) emit(k, {count:1});
	} else {
		emit('/root', {count:1}); 
	}
}

var reduce = function(key, values) {
	var sum = 0;
	values.forEach(function(value) {
		sum += value['count'];
	});
	return {count: sum};
}


db.images.mapReduce(map, reduce, {out: {inline:1}, query:query})