custom symbol generator

index.js

function mySymbols(){

  var symbol = d3.svg.symbol();
  var my_types = []; // our other types

  my_types.NewSymbolName = function(size){
    return 'Custom Symbol 1 Path'
  }

  var me = function(datum, index){

    var type = symbol.type(), size = symbol.size();
    if(type instanceof Function){
      type = type(datum, index);
    }
    if(size instanceof Function){
      size = size(datum, index);
    }

    // generating a built in type.
    if(d3.svg.symbolTypes.indexOf(type) !== -1) {
      return symbol(datum, index);
    }
    return my_types[type](size);
  };

  var my_size = symbol.size();
  me.size = function(size){
    if(arguments.length){
      symbol.size(size);
      return me;
    }
    return symbol.size();
  };

  var my_type = symbol.type();
  me.type = function(type){
    if(arguments.length){
      symbol.type(type);
      return me;
    }
    return symbol.type();
  };
  return me;
};