Can I use object, XMLHttpRequest and WebSocket as types?

Cocos Creator
#1

hi,
I am writing code in typescript where I need a variable to act as a javascript object. can I use object as its type? also, I am using WebSocket and XMLHttpRequest objects. do I need to declare their respective variables of types WebSocket and XMLHttpRequest? also, do I need to do :

@property(typename)
variablename:typename = null;

or just :

@property
variablename:typename = null;

please can someone tell me the difference between the two ways?

thanks!