Change a `as const` object into a type that is more broadly applicable

Creating a Generic Type from an Immutable Object Using "as const"

Consider the following immutable object:

const usersDefaultValues = {
  firstName: '',
  isGuest: false
} as const

We aim to generate the following type/interface based on this object:

type DefaultValuesSchema = {
  firstName: string
  isGuest: boolean
}

Answer №1

Perhaps you are seeking a solution similar to this:

const defaultUserValues = {
  firstName: '',
  isGuest: false
} as const

type Modified<T> = {
  [P in keyof T]: T[P] extends boolean ? boolean : T[P] extends string ? string : never;
}

type Output = Modified<typeof defaultUserValues>

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