interface

test.AsymmetricMatchersBuiltin

interface AsymmetricMatchersBuiltin

  • constructor: (...args: any[]) => any | new (...args: any[]) => any
    ): any;

    Matches anything that was created with the given constructor. Use it inside toEqual or toBeCalledWith instead of a literal value.

    function randocall(fn) {
  return fn(Math.floor(Math.random() * 6 + 1));
}

test('randocall calls its callback with a number', () => {
  const mock = jest.fn();
  randocall(mock);
  expect(mock).toBeCalledWith(expect.any(Number));
});
  • anything(): any;

    Matches anything but null or undefined. Use it inside toEqual or toBeCalledWith instead of a literal value. For example, to check that a mock function is called with a non-null argument:

    test('map calls its argument with a non-null argument', () => {
  const mock = jest.fn();
  [1].map(x => mock(x));
  expect(mock).toBeCalledWith(expect.anything());
});
  • arrayContaining<E = any>(
    arr: readonly E[]
    ): any;

    Matches any array made up entirely of elements in the provided array. Use it inside toEqual or toBeCalledWith instead of a literal value.

    Optionally, pass a type for the elements as a generic argument.

  • num: number,
    numDigits?: number
    ): any;

    Matches a number close to the provided value. Use it when comparing floating point numbers in object properties or array items. To compare a number directly, use .toBeCloseTo instead.

    The optional numDigits argument limits the number of digits to check after the decimal point. For the default value 2, the test criterion is Math.abs(expected - received) < 0.005 (that is, 10 ** -2 / 2).

  • obj: object
    ): any;

    Matches any object that recursively matches the provided keys.

    Optionally, pass a type for the object as a generic argument. This ensures that the object contains the desired structure.

  • str: string | String
    ): any;

    Matches any received string that contains the exact expected string

  • regex: string | String | RegExp
    ): any;

    Matches any received string that matches the expected string or regular expression