type-fest@3 - How to declare optional properties in JsonObject?
After the update to version 3.0.0, it is no longer possible to have optional properties on a JsonObject:
import { JsonObject } from "type-fest";
interface MyObject extends JsonObject {
optionalProp?: string
}Gives a TypeError:
(property) MyObject.optionalProp?: string | undefined
Property 'optionalProp' of type 'string | undefined' is not assignable to 'string' index type '((string | number | boolean | JsonObject | JsonArray) & (string | number | boolean | JsonObject | JsonArray | undefined)) | null'.ts(2411)
How should this type be used correctly? The code above worked fine with version 2.x.
sindresorhus / type-fest
A collection of essential TypeScript types
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