d3.js将对象推入另一个具有对象数组的对象

I already have object(called callbackData) which already has [Object,Object,Object,Object] structure.(these are real Object). When I push in callbackData1(which is also object) into callbackData and then look into callbackData, I see that callbackData1 object was pushed in as Array(while previous object remain object).I already have object(called callbackData) whic