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@imkrish

imkrish/deep-read-only.ts

Last active Apr 27, 2019
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type DeepReadonlyObject<T> = { readonly [K in keyof T]: DeepReadonly<T[K]> };
type DeepReadonly<T> = T extends (infer E)[][]
? ReadonlyArray<ReadonlyArray<DeepReadonlyObject<E>>>
: T extends (infer E)[]
? ReadonlyArray<DeepReadonlyObject<E>>
: T extends object
? DeepReadonlyObject<T>
: T;
interface ITodo {
task: string;
done: boolean;
}
interface IRootState {
userId: string;
showCompletedOnly: boolean;
todoTypes: string[];
todos: ITodo[];
iconGrid: string[][];
}
type ReadonlyRootState = DeepReadonly<IRootState>;
let rootState: ReadonlyRootState; // Typescript service will prevent this variable from mutation
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