Before You File a Proposal Please Confirm You Have Done The Following...

• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Link to the rule's documentation

https://typescript-eslint.io/rules/prefer-nullish-coalescing

Description

In cases where an assignment is made to a nullish variable via ||=, it'd be nice if ??= was suggested instead.

Fail

let foo: Map<string, string> | undefined;

foo ||= new Map();

foo = foo || new Map(); // These are already handled in prefer-nullish-coalescing.
(foo || new Map()).get("key");

Pass

let foo: Map<string, string> | undefined;

foo ??= new Map();

foo = foo ?? new Map(); // These are already handled in prefer-nullish-coalescing.
(foo ?? new Map()).get("key");

Additional Info

No response