# vitest/prefer-snapshot-hint

> Require a hint on `toMatchSnapshot()` and `toThrowErrorMatchingSnapshot()`

Snapshots in a `.snap` file are named after the test and numbered, like `renders the menu 1` and `renders the menu 2`. With several in one test, you can't tell which snapshot belongs to which `expect`, and adding one in the middle renumbers the rest. A hint becomes part of the name, as in `renders the menu > closed 1`.

By default a hint is only required in a test that has more than one snapshot. Inline snapshots aren't checked.

{/* Generated by src/codegen/lint-rule-docs.ts. Do not edit this section. */}

## Configure

Off by default. To turn it on:

```toml bunfig.toml
[lint.rules]
"vitest/prefer-snapshot-hint" = "error" # or "warn"
```

Every option, set to its default:

```toml bunfig.toml
[lint.rules]
"vitest/prefer-snapshot-hint" = ["error", "multi"] # "multi" or "always"
```

{/* End of the generated section. */}

## Examples

Reported:

{/* bad {"count": 2} */}
```ts
import { expect, test } from "vitest";

test("renders the menu", () => {
  expect(renderMenu({ open: false })).toMatchSnapshot();
  expect(renderMenu({ open: true })).toMatchSnapshot();
});
```

Not reported:

{/* good */}
```ts
import { expect, test } from "vitest";

test("renders the menu", () => {
  expect(renderMenu({ open: false })).toMatchSnapshot("closed");
  expect(renderMenu({ open: true })).toMatchSnapshot("open");
});

test("renders the footer", () => {
  expect(renderFooter()).toMatchSnapshot();
});
```

A single argument only counts as a hint if it's a string or a template literal. Property matchers or a variable are reported:

{/* bad {"count": 2} */}
```ts
import { expect, test } from "vitest";

test("creates users", () => {
  expect(createUser("Ada")).toMatchSnapshot({ id: expect.any(Number) });
  expect(createUser("Grace")).toMatchSnapshot(hint);
});
```

With property matchers, the hint is the second argument:

{/* good */}
```ts
import { expect, test } from "vitest";

test("creates users", () => {
  expect(createUser("Ada")).toMatchSnapshot({ id: expect.any(Number) }, "first user");
  expect(createUser("Grace")).toMatchSnapshot({ id: expect.any(Number) }, "second user");
});
```

## Options

```toml bunfig.toml
[lint.rules]
"vitest/prefer-snapshot-hint" = ["error", "always"]
```

| Option | What it does |
| --- | --- |
| `"multi"` (default) | Require a hint if the test has more than one snapshot. |
| `"always"` | Require a hint on every snapshot. |

{/* bad {"options": ["always"]} */}
```ts
import { expect, test } from "vitest";

test("renders the footer", () => {
  expect(renderFooter()).toMatchSnapshot();
});
```