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

• My proposal specifically checks TypeScript syntax, or it proposes a check that requires type information to be accurate.
• My proposal is not a "formatting rule"; meaning it does not just enforce how code is formatted (whitespace, brace placement, etc).
• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

Checking for array membership using in is a common new JS developer mistake - it looks like it should work but it does not since in checks for properties, and array values are not properties.

Fail Cases

const arr = ['a', 'b', 'c'];
const inArray = 'a' in arr;

Pass Cases

const arr = ['a', 'b', 'c'];
const inArray = arr.includes('a');

Additional Info

There is a very similar https://typescript-eslint.io/rules/no-for-in-array rule for for-in loops specifically