to have an item satisfying

• <array-like> [not] to have an item [exhaustively] satisfying <assertion>
• <array-like> [not] to have an item [exhaustively] satisfying <any>

Asserts an array (or array-like object) contains at least one item that satisfies a given value, function or other assertion.

Note that this assertion fails if passed an empty array as the subject.

expect([{ a: 1 }, { b: 2 }], 'to have an item satisfying', { a: 1 });
 
expect([0, 1, 2, 3, 4], 'to have an item satisfying', 'to be a number');
 
expect(
  [0, 1, 2, 3, 4],
  'to have an item satisfying',
  expect.it(function (item) {
    expect(item, 'to be a number');
  })
);
 
expect(
  [[1], ['foo']],
  'to have an item satisfying',
  'to have an item satisfying',
  'to be a number'
);
 
expect(
  [-1, -2, 3],
  'to have an item satisfying',
  expect.it('to be a number').and('to be positive')
);

The expected value will be matched against the value with to satisfy semantics, so you can pass any of the values supported by to satisfy. To use strict to satisfy semantics, you can use the "exhaustively" flag:

expect([{ a: 1, b: 2 }], 'to have a value satisfying', { a: 1 });

expect([{ a: 1, b: 2 }], 'to have a value exhaustively satisfying', { a: 1 });

expected [ { a: 1, b: 2 } ] to have a value exhaustively satisfying { a: 1 }

In case of a failing expectation you get the following output:

expect(
  [
    ['0', '1'],
    ['5', '6'],
    ['7', '8'],
  ],
  'to have an item satisfying',
  'to have an item satisfying',
  'to be a number'
);

expected [ [ '0', '1' ], [ '5', '6' ], [ '7', '8' ] ]
to have an item satisfying to have an item satisfying to be a number

Here a another example:

expect(
  [0, -1, -2, -3, -4],
  'to have an item satisfying',
  expect.it('to be a number').and('to be positive')
);

expected [ 0, -1, -2, -3, -4 ] to have an item satisfying
expect.it('to be a number')
        .and('to be positive')

This assertion can be negated using the not flag:

expect(
  [0, -1, -2, -3, -4],
  'not to have an item satisfying',
  expect.it('to be a number').and('to be negative')
);

expected [ 0, -1, -2, -3, -4 ] not to have an item satisfying
expect.it('to be a number')
        .and('to be negative')
 
[
  
0,
-1, // should be removed
-2, // should be removed
-3, // should be removed
-4 // should be removed
]