Mixin: Property 'messageRawPayload' of exported class expression may not be private or protected.ts(4094)

[huan]

The Problem

Mixin does not allow the use of protected and private with property/method

The Solution

1. Change them with public and a _ prefix?
2. Provide a PuppetInterface by defining a ProtectedMethods type to calculate from Omit<Puppet, ProtectedMethods>

Links

• SO: Why do they say "may not" for things which people shouldn't do
• SO: Typescript allows to use proper multiple inheritances with mixins, but fails to create declaration files
• Generating type definitions for mixin classes with protected members microsoft/TypeScript#17744 (comment)
• mixin-ization Puppet Abstract Class #156

[huan]

Finally, we use a PuppetInterface to remove the protected methods.