Ability to collect defined metadata property names

[hlege]

Is there a way to collect the decorated property names from a prototype without knowing the property names in advance?

It is a useful feature for an orm, ioc and other stuff.

Right know Reflect.getMetadataKeys(fn.prototype) returns an empty array. It would be useful to return the annotated property names if the second argument is undefined.
Maybe Reflect.getMetadataPropertyNames(fn.prototype)

Example:

 const fn:Function = ...;

 const propertyNames = Reflect.getMetadataKeys(fn.prototype);
 for (const name of propertyNames){
     const cachable = Reflect.hasMetadata("CachableMetaKey", fn.prototype, name);
     if (cachable) {
       //do stuff
     }
 }

[MichalLytek]

Ping @hlege, have you found a solution?
@rbuckton can you help us? 😉

[navels]

See #35