Proposal: New rule for prohibiting usage of mutating array methods

[yenbekbay]

It would be great to have a rule that warns about using mutating array methods without explicitly typing the arrays with ReadonlyArray.

Context

In some cases, it's not desirable to explicitly type arrays with ReadonlyArray. For example, when the type of an array can be automatically inferred:

const makeComplexObj = (...) => ({a: new A(...), b: new B(...)});

const someArr = [makeComplexObj(...), makeComplexObj(...), ...];

vs

const someArr: ReadonlyArray<{
  a: A,
  b: B,
}> = [makeComplexObj(...), makeComplexObj(...), ...];

As you can see, typing such an array explicitly can be a bit cumbersome/verbose.

Proposal

Similar to how the no-object-mutation rule deals with objects, the rule would use type information to detect arrays and warn about using methods such as push, pop, shift and others.

[jonaskello]

This sounds like a nice complement to the no-object-mutation rule, something likeno-array-mutation. I would be happy to take a PR for it, or I'll look into it when I have some spare time.

[dalen]

This is great, especially considering typing as ReadonlyArray causes microsoft/TypeScript#15972