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Rslint

    prefer-each

    Added in v0.6.0

    Configuration

    rslint.config.ts
    import { defineConfig, jestPlugin } from '@rslint/core';

export default defineConfig([
  jestPlugin.configs.recommended,
  {
    rules: {
      'jest/prefer-each': 'error',
    },
  },
]);

    Rule Details

    Prefer .each over wrapping describe/test/it in native for loops, for clearer output and easier filtering. Loops inside a test function are ignored.

    Examples of incorrect code for this rule:

    for (const number of getNumbers()) {
  it('is greater than five', function () {
    expect(number).toBeGreaterThan(5);
  });
}

for (const [input, expected] of data) {
  beforeEach(() => setupSomething(input));

  test(`results in ${expected}`, () => {
    expect(doSomething()).toBe(expected);
  });
}

    Examples of correct code for this rule:

    it.each(getNumbers())(
  'only returns numbers that are greater than seven',
  number => {
    expect(number).toBeGreaterThan(7);
  },
);

describe.each(data)('when input is %s', ([input, expected]) => {
  beforeEach(() => setupSomething(input));

  test(`results in ${expected}`, () => {
    expect(doSomething()).toBe(expected);
  });
});

// we don't warn on loops _in_ test functions because those typically involve
// complex setup that is better done in the test function itself
it('returns numbers that are greater than five', () => {
  for (const number of getNumbers()) {
    expect(number).toBeGreaterThan(5);
  }
});

    Original Documentation