Support Typescript's readonly array, map and set types

[Mossop]

🚀 Feature Proposal

Typescript has some utility types, ReadonlyArray, ReadonlySet and ReadonlyMap<K, V> but immer doesn't seem to correctly handle these in the Immutable and Draft types.

Motivation

More consistent type checking is in everyone's best interests!

Can this be solved in user-land code?

I could probably write my own typings to override immer's but I would expect this to be something included in immer itself.

Example

import { Draft, produce } from "immer";

let foo: ReadonlySet<string> = new Set();

produce(foo, (draft: Draft<ReadonlySet<string>>) => {
  draft.set("bar");
});

Result:

`Property 'set' does not exist on type '{ forEach: (callbackfn: (value: string, value2: string, set: ReadonlySet) => void, thisArg?: any) => void; has: (value: string) => boolean; size: number; entries: { ...; }; keys: { ...; }; values: { ...; }; }'

[mweststrate]

Implemented through #495 -> #506

[aleclarson]

🎉 This issue has been resolved in version 5.3.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀