How to annotate enum fields

[haraldk]

It would be nice if you could add some documentation on how to annotate enum fields.

As an example, I have:

export enum Currency {
  USD,
  EUR
}

class Price {
  private value: number; // It's really a "BigDecimal" type don't worry ;-)
  private currency: Currency;
}

I have tried the following:

No annotation:

class Price {
  // ...
  private currency: Currency;

Result:

No error. No conversion ("currency" is a string, as in the original JSON).

Take two, with @dataType() annotation:

class Price {
  // ...

  @dataType(Currency)
  private currency: Currency;

Result:

Error (I'm no TypeScript expert, but it seems that enums don't have constructors), "Cannot read property 'constructor' of undefined"

TypeError: Cannot read property 'constructor' of undefined
    at Object.getTypeOfCtor (http://localhost:4200/vendor.js:162163:37)
    at deserialize (http://localhost:4200/vendor.js:162083:42)
	...

Take three, with additional @converters():

class Price {
  // ...

  @dataType(Currency)
  @converters({
    'string': (currency: string) => Currency[currency]
  })
  private currency: Currency;

Result:

Exaclty the same error as the previous attempt, "Cannot read property 'constructor' of undefined"

TypeError: Cannot read property 'constructor' of undefined
    at Object.getTypeOfCtor (http://localhost:4200/vendor.js:162163:37)
    at deserialize (http://localhost:4200/vendor.js:162083:42)
	...

In desperation, with only @converters():

class Price {
  // ...

  @converters({
    'string': (currency: string) => Currency[currency]
  })
  private currency: Currency;

Result:

Unsurprisingly this didn't work, but the error message is a little odd. Not sure why it expects a string, when the type is an enum? "Converter output type invalid for property Price.currency, expected string received number."

Error: Converter output type invalid for property Price.currency, expected string received number.
    at deserialize (http://localhost:4200/vendor.js:162107:35)
	...

So... How am I supposed to do it? Or is this a missing feature?

Best regards,

--
Harald K