jestjs/jest · error · Error

Error: `.each` called with an empty Array of table data.

Error message

Error: `.each` called with an empty Array of table data.

What it means

Thrown by `validateArrayTable` when the array passed to `.each` has zero elements (`table.length === 0`). An empty table means no test cases will be generated, which is almost certainly a mistake — the developer likely forgot to populate the data.

Solutions

Populate the array with at least one test case row.
If the array is dynamically generated, add a guard to skip the `describe.each`/`test.each` block when the array is empty.
Check the data source or filter logic to ensure rows are present.

Example fix

// before
const cases = fixtures.filter(f => f.active); // empty if none active
test.each(cases)('test %j', (c) => {});

// after
const cases = fixtures.filter(f => f.active);
if (cases.length > 0) {
  test.each(cases)('test %j', (c) => {});
}

Defensive patterns

Strategy: validation

Validate before calling

// Guard dynamic .each arrays
function runEachIfData(testFn, table) {
  if (!Array.isArray(table) || table.length === 0) {
    console.warn('Skipping .each — table is empty');
    return;
  }
  return testFn(table);
}

Type guard

function isNonEmptyArray<T>(value: unknown): value is T[] {
  return Array.isArray(value) && value.length > 0;
}

Prevention

When generating test data dynamically, guard the .each call with a length check.
Log or warn when test data sources produce zero rows.
In CI, fail if expected test case counts drop to zero unexpectedly.

When it happens

Trigger: Passing `[]` to `test.each([])`. Passing a variable that was initialized as an empty array but never populated (e.g. from a filtered/mapped result that yielded nothing).

Common situations: Filtering test data dynamically and the filter eliminates all rows. Loading data from an external source that returned an empty result. Placeholder/scaffold code left with `[]`.

Related errors

AI-assisted analysis of jestjs/jest@8e6d128e4a (2026-08-10). Data as JSON: /api/errors/39069c4f33e9186f. Report an issue: GitHub.

Appendix: source

Thrown at packages/jest-each/src/validation.ts:42

          min: true,
        })}\n`,
    );
  }

  if (isTaggedTemplateLiteral(table)) {
    if (isEmptyString(table[0])) {
      throw new Error(
        'Error: `.each` called with an empty Tagged Template Literal of table data.\n',
      );
    }

    throw new Error(
      'Error: `.each` called with a Tagged Template Literal with no data, remember to interpolate with ${expression} syntax.\n',
    );
  }

  if (isEmptyTable(table)) {
    throw new Error(
      'Error: `.each` called with an empty Array of table data.\n',
    );
  }
};

const isTaggedTemplateLiteral = (array: any) => array.raw !== undefined;
const isEmptyTable = (table: Array<unknown>) => table.length === 0;
const isEmptyString = (str: string | unknown) =>
  typeof str === 'string' && str.trim() === '';

export const validateTemplateTableArguments = (
  headings: Array<string>,
  data: TemplateData,
): void => {
  const incompleteData = data.length % headings.length;
  const missingData = headings.length - incompleteData;

  if (incompleteData > 0) {

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