why does type prop needs to be static ?

[gpeel]

In the code is seems that we could do without "static" but when trying the compiler argues that the constructor is not implemented which is quite strange.

Is this a wanted design constraint ?

export class CreateTask implements ActionDef {
  type: string = 'pipo';   // static keyword removed
  constructor(public task: Task) {
  }
}

this code will raise :

TS2420: Class 'CreateTask' incorrectly implements interface 'ActionDef<any, any>'.  
 Type 'CreateTask' provides no match for the signature 'new (...args: any[]): any'.