# jest/prefer-each

> Require `test.each` and `describe.each` instead of a loop around tests

`test.each` and `describe.each` take the list of cases as an argument and fill in the title for each one. A `for` loop around `test` does the same thing with more code, and you have to build every title by hand.

The rule reports `for`, `for...of` and `for...in` loops that contain a `test`, a `describe` or a hook such as `beforeEach`. A loop inside a test is fine. `while` loops and `cases.forEach(...)` around a test aren't reported.

{/* 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/prefer-each" = "error" # or "warn"
```

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

## Examples

Reported:

{/* bad */}
```ts
import { expect, test } from "@jest/globals";

const cases = [
  [1, 2],
  [2, 4],
];

for (const [input, expected] of cases) {
  test(`doubles ${input}`, () => {
    expect(input * 2).toBe(expected);
  });
}
```

Not reported:

{/* good */}
```ts
import { expect, test } from "@jest/globals";

test.each([
  [1, 2],
  [2, 4],
])("doubles %i", (input, expected) => {
  expect(input * 2).toBe(expected);
});

test("every price is positive", () => {
  for (const price of [5, 10]) {
    expect(price).toBeGreaterThan(0);
  }
});
```