prefer-in-document: `.toHaveLength(1)` vs `.toBeInTheDocument()`

• eslint-plugin-jest-dom version: 3.8.1
• node version: 16.1.0
• npm version: 7.11.1

Relevant code or config

expect(screen.queryAllByRole('option')).toHaveLength(2);
// some action here
expect(screen.queryAllByRole('option')).toHaveLength(1);

What you did: I want to ensure there is only one option.

What happened:

The rule wants this to be

expect(screen.queryByRole('option')).toBeInTheDocument();

Reproduction repository:

Problem description: It’s not the same thing! I cannot assert that there is only one option now.

Suggested solution: prefer-in-document should allow .toHaveLength(1). Or there should be an option at least.

[mdotwills]

Based on the discussion in this thread, I’ve put together this truth table of selector type vs assertion style:

Selector type	.toBeInTheDocument()	.toHaveLength(1)	.toHaveLength(0)
(*By*)	✅ correct usage, no change	Did you mean to use (*AllBy*)?	🔧 replace with .not.toBeInTheDocument()
(*AllBy*)	🔧 replace with .toHaveLength(1)	✅ correct usage, no change	✅ correct usage, no change

The resolution of the (*By*) ∩ .toHaveLength(1) suggestion of did you mean to use (*AllBy*) could resolve as

• Yes, then replace (*By*) with (*AllBy*), leaving expect((*AllBy*)).toHaveLength(1),
• No, then replace .toHaveLength(1) with .toBeInTheDocument() , leaving expect((*By*)).toBeInTheDocument()

both of which are stable states.

[mdotwills]

I like your suggestion @nstepien 👍 I’ll have a crack at implementing that