Typescript: Converting typescript interface to a type that represents what it would be after a json.-CodePudding

Say I have a simple interface:

interface Calendar {
  dates: Date[]
  add: () => {}
}

If a calendar object gets Json.stringified, the type becomes like this:

interface StringifiedCalendar {
  dates: string[]
  // Function would dissappear
}

Is there a simple way to convert between the original interface to the stringified version easily? My use case is that rest API would stringify objects, and I'd like to reuse the original type definitions from the backend without rewriting.

CodePudding user response：

This is at least a partial solution. The editor on the playground still reports that jcal has an add property, but if one tries to use it as a method, an error is reported.

interface Calendar {
  dates: Date[]
  add: () => {}
}

type Jsonized<T> = T extends object ? {
    [K in keyof T]: 
        T[K] extends Function ? never : 
        T[K] extends Date ? string :
        T[K] extends number ? number :
        T[K] extends string ? string :
        Jsonized<T[K]>
} : T;

declare let jcal: Jsonized<Calendar>;
jcal.add();

Playground