promise-any.md

title
promise.any

expect.promise.any(...)

This method will find all promises in the given structure and return a promise that will be fulfilled when any of the promises in the structure have been fulfilled. If all of the promises are rejected, the resulting promise will be rejected with the errors.

Let's make an asynchronous assertion that we can use for the examples:

expect.addAssertion('to be a number after a short delay', function (expect, subject) {
  return expect.promise(function (run) {
    setTimeout(run(function () {
        expect(subject, 'to be a number');
    }), 0);
  });
});

See the promise documentation for more details on how expect.promise works.

The following code snippet creates a promise that will be fulfilled when any of the promises in the nested structure has been fulfilled.

return expect.promise.any({
  foo: [
    expect('42', 'to be a number after a short delay')
  ],
  bar: expect([0, 1, 2], 'to have items satisfying',
                         expect.it('to be a number after a short delay')),

  baz: expect({ a: '1', b: 2 }, 'to have values satisfying',
                                'to be a number after a short delay')
});

The following code snippet create a promise that will rejected when all of the promises in the nested structure have been rejected:

return expect.promise.any({
  foo: [
    expect('42', 'to be a number after a short delay')
  ],
  bar: expect([0, '1', 2], 'to have items satisfying',
                           expect.it('to be a number after a short delay')),

  baz: expect({ a: '0', b: 1 }, 'to have values satisfying',
                                'to be a number after a short delay')
}).caught(function (aggregateError) {
  // Let's reformat the error a bit
  expect.fail(function (output) {
    output.error(aggregateError.message);
    var errors = [];
    for (var i = 0; i < aggregateError.length; i += 1) {
      aggregateError[i].serializeMessage(expect.outputFormat())
      errors.push(aggregateError[i]);
    }

    errors.sort(function (a, b) { // Make the output stable
      if (a.message < b.message) return -1;
      if (a.message > b.message) return 1;
      return 0;
    });

    output.indentLines();
    errors.forEach(function (e, i) {
      output.nl().i().text(i + ': ').block(e.getErrorMessage({ output: output }));
    });
  });
});

aggregate error
  0: expected '42' to be a number after a short delay
  1: expected [ 0, '1', 2 ]
     to have items satisfying expect.it('to be a number after a short delay')

     [
       0,
       '1', // should be a number after a short delay
       2
     ]
  2: expected { a: '0', b: 1 }
     to have values satisfying to be a number after a short delay

     {
       a: '0', // should be a number after a short delay
       b: 1
     }