Array

.toBeArray()

Use .toBeArray when checking if a value is an Array.

test('passes when value is an array', () => {
  expect([]).toBeArray();
  expect([1]).toBeArray();
  expect(true).not.toBeArray();
});

Tests

.toBeArrayOfSize()

Use .toBeArrayOfSize when checking if a value is an Array of size x.

test('passes when value is an array', () => {
  expect([]).toBeArrayOfSize(0);
  expect([1]).toBeArrayOfSize(1);
  expect(true).not.toBeArrayOfSize(1);
});

Tests

.toIncludeAllMembers([members])

Use .toIncludeAllMembers when checking if an Array contains all of the same members of a given set.

test('passes when given array values match the members of the set', () => {
  expect([1, 2, 3]).toIncludeAllMembers([2, 1, 3]);
  expect([1, 2, 2]).toIncludeAllMembers([2, 1]);
});

Tests

.toIncludeAllPartialMembers([members])

Use .toIncludeAllPartialMembers when checking if an Array contains all of the same partial members of a given set.

test('passes when given array values match the partial members of the set', () => {
  expect([{ foo: 'bar', baz: 'qux' }]).toIncludeAllPartialMembers([{ foo: 'bar' }]);
});

Tests

.toIncludeAnyMembers([members])

Use .toIncludeAnyMembers when checking if an Array contains any of the members of a given set.

test('passes when given array values match any of the members in the set', () => {
  expect([1, 2, 3]).toIncludeAnyMembers([2, 1, 3]);
  expect([1, 2, 2]).toIncludeAnyMembers([2]);
  expect([1, 2, 2]).not.toIncludeAnyMembers([3]);
});

Tests

.toIncludeSameMembers([members])

Use .toIncludeSameMembers when checking if two arrays contain equal values, in any order.

test('passes when arrays match in a different order', () => {
  expect([1, 2, 3]).toIncludeSameMembers([3, 1, 2]);
  expect([{ foo: 'bar' }, { baz: 'qux' }]).toIncludeSameMembers([{ baz: 'qux' }, { foo: 'bar' }]);
});

Tests

.toPartiallyContain(member)

Use .toPartiallyContain when checking if any array value matches the partial member.

test('passes when a string has a given substring', () => {
  expect([{ foo: 'bar', baz: 'qux', bax: 'zax' }]).toPartiallyContain({ foo: 'bar' });
  expect([{ foo: 'bar', baz: 'qux', bax: 'zax' }]).toPartiallyContain({ baz: 'qux' });
  expect([{ foo: 'bar', baz: 'qux', bax: 'zax' }]).not.toPartiallyContain({ foo: 'qux' });
});

Tests

.toSatisfyAll(predicate)

Use .toSatisfyAll when you want to use a custom matcher by supplying a predicate function that returns a Boolean for all values in an array.

test('passes when all values in array pass given predicate', () => {
  const isOdd = el => el % 2 === 1;
  expect([1, 3, 5, 7]).toSatisfyAll(isOdd);
  expect([1, 3, 4, 5, 7]).not.toSatisfyAll(isOdd);
});

Tests

.toSatisfyAny(predicate)

Use .toSatisfyAny when you want to use a custom matcher by supplying a predicate function that returns true for any matching value in an array.

test('passes when any value in array pass given predicate', () => {
  const isOdd = el => el % 2 === 1;
  expect([2, 3, 6, 8]).toSatisfyAny(isOdd);
  expect([2, 4, 8, 12]).not.toSatisfyAny(isOdd);
});

Tests

.toBeInRange(min, max)

Use .toBeInRange when checking if an array has elements in range min (inclusive) and max (inclusive).

test('passes when given array is in range', () => {
  expect([4, 5, 7, 9]).toBeInRange(4, 10);
  expect([12, 13, 15, 17]).not.toBeInRange(4, 9);
});

Tests