Deep Read Only Typescript 3.8

DeepReadOnly.ts

export type DeepReadOnly<P> =
  P extends undefined | null | boolean | string | number | Function 
    ? P :
  P extends Array<infer T> 
    ? ReadonlyArray<DeepReadOnly<T>> :
  P extends Map<infer K, infer V> 
    ? ReadonlyMap<DeepReadOnly<K>, DeepReadOnly<V>> :
  P extends Set<infer M> 
    ? ReadonlySet<DeepReadOnly<M>> : 
  { readonly [K in keyof P]: DeepReadOnly<P[K]> }



export type DRO<P> = DeepReadOnly<P>

Usage.tsx

import {DeepReadOnly} from "deep-read-only"
const globalStore: DeepReadOnly<TodoStore> = new TodoStore()

export const App = (props: DeepReadOnly<{ store: TodoStore }>) => {
  return <button onClick={
                 () => {  props.store.insert("Hey") }
                         }>
          {props.store.todos.length > 0 && props.store.todos[0].text}
          </button>
}