# jest/no-large-snapshots

> Disallow snapshots that are longer than a set number of lines

Nobody reads a snapshot that's several hundred lines long in a review. When it changes, people update it without looking, and then the test passes no matter what the code does. A short snapshot, or an assertion on the few values that matter, still tells you something when it fails.

The rule counts the lines in the first argument to `toMatchInlineSnapshot` and `toThrowErrorMatchingInlineSnapshot`. The limit is 50 lines. A snapshot that comes after a property matcher isn't counted.

{/* 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]
"jest/no-large-snapshots" = "error" # or "warn"
```

Every option, set to its default. The ones that are commented out are unset by default.

```toml bunfig.toml
[lint.rules]
"jest/no-large-snapshots" = ["error", {
  # inlineMaxSize = <value>,
  maxSize = 50,
  allowedSnapshots = {},
}]
```

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## Examples

These examples set `inlineMaxSize` to `3` to stay short.

Reported:

{/* bad {"options": [{"inlineMaxSize": 3}]} */}
```ts
import { expect, test } from "@jest/globals";

test("loads the user", () => {
  expect(loadUser(1)).toMatchInlineSnapshot(`
    {
      "email": "ada@example.com",
      "id": 1,
      "name": "Ada",
    }
  `);
});
```

Not reported:

{/* good {"options": [{"inlineMaxSize": 3}]} */}
```ts
import { expect, test } from "@jest/globals";

test("loads the user", () => {
  const user = loadUser(1);
  expect(user.name).toBe("Ada");
  expect(user.email).toMatchInlineSnapshot(`"ada@example.com"`);
});
```

## Options

| Option | Default | What it does |
| --- | --- | --- |
| `inlineMaxSize` | the value of `maxSize` | The most lines an inline snapshot can have. |
| `maxSize` | `50` | The most lines a snapshot in a `.snap` file can have. |
| `allowedSnapshots` | `{}` | Snapshots in `.snap` files that can have any length. Each key is the absolute path to a `.snap` file. Its value is a list of snapshot names or regular expressions. |

`bun lint` skips `.snap` files unless you ask for them:

```sh
bun lint --ext .snap
```

With an ESLint config, list `.snap` files under `files` instead. An oxlint config never lints them. If `.snap` files aren't linted, `maxSize` only sets the default for `inlineMaxSize`, and `allowedSnapshots` has no effect.

```json .oxlintrc.json
{
  "plugins": ["jest"],
  "rules": {
    "jest/no-large-snapshots": ["error", { "inlineMaxSize": 20 }]
  }
}
```

Without `inlineMaxSize`, `maxSize` applies to inline snapshots:

{/* bad {"options": [{"maxSize": 3}]} */}
```ts
import { expect, test } from "@jest/globals";

test("lists the roles", () => {
  expect(roles()).toMatchInlineSnapshot(`
    [
      "admin",
      "editor",
      "viewer",
    ]
  `);
});
```