Exploring EcmaScript Decorators

An ES2016 decorator is an expression which returns a function and can take a target, name and property descriptor as arguments. You apply it by prefixing the decorator with an @ character and placing this at the very top of what you are trying to decorate. Decorators can be defined for either a class, a method or a property.

Param decorators

Nest provides a set of useful param decorators that you can use together with the HTTP route handlers. 

@Request(), @Req()	req
@Response(), @Res()	res
@Next()	next
@Session	req.session
@Param(param?: string)	req.params / req.params[param]
@Body(param?:string)	req.body / req.body[param]
@Query(param?:string)	req.query / req.query[param]
@Headers(param?:string)	req.headers / req.headers[param]
@Ip()	req.ip
@HostParam()	req.hosts