There is also class-transformer[1] and class-validator[2] which also do the same job but integrate a bit better into the whole typescript cosmos.
[1] https://github.com/typestack/class-transformer [2] https://github.com/typestack/class-validator
Method implies use of this, which implies they are probably not first class - such would be functions cannot be passed or returned, as the this reference won’t be bound if called as a function.
I use [serializr](https://github.com/mobxjs/serializr) to convert json to my classes, and afterwards I can have all the deligtful methods I want. :-) I love the code clarity this gives, methods are where they are most logical, instead of on some helper object.