.empty fails for mongoose arrays

[tusbar]

Hey,

The new .empty assertion that was introduced in #499 fails for mongoose arrays.

You can reproduce with the following:

var mongoose = require('mongoose');

var schema = new mongoose.Schema({
    array: [{
        prop: String
    }]
});

var Foo = mongoose.model('Foo', schema);
var foo = new Foo();

it('should be empty', function () {
    expect(foo.array).to.be.empty;
});

It fails with a AssertionError: expected [] to be empty.

I am using mongoose @ 4.1.12 but I’m not sure that’s relevant to the issue.

[keithamus]

Hey @tusbar thanks for the issue.

This is probably because the array has some keys assigned to it. What do you get back from Object.keys(foo.array)?

[tusbar]

@keithamus it does have keys as it is not a real Array, but it implements the Array API (or at least some of it).

> console.log(Object.keys(foo.array));
[ '_cast',
  'id',
  'toObject',
  'inspect',
  'create',
  'notify',
  '_atomics',
  '_parent',
  '_markModified',
  '_registerAtomic',
  '$__getAtomics',
  'hasAtomics',
  '_mapCast',
  'push',
  'nonAtomicPush',
  '$pop',
  'pop',
  '$shift',
  'shift',
  'pull',
  'splice',
  'unshift',
  'sort',
  'addToSet',
  'set',
  'indexOf',
  'remove',
  'isMongooseArray',
  'isMongooseDocumentArray',
  'validators',
  '_path',
  '_schema',
  '_handlers' ]

[keithamus]

Okay, so its not empty then? In that case, expect(foo.array).to.be.empty is failing correctly, right?

Is your issue that the message isn't good enough? I guess it should say something like AssertionError: expected [ isMongooseArray: true, _atomics: [Object], validators: [], _path: '' ] to be empty. instead.

[tusbar]

@keithamus the issue is that this used to work pre-3.3.0. And it is a breaking change.

I am sure that many people use chai and mongoose together and will pull their hair out trying to understand what’s going on (especially with that expected [] to be empty error message).

I seems that you want .empty to be strictly for Array and not have compatibility for Array-like objects – if so, 3.3.0 should probably be tagged 4.0.0.

[keithamus]

Hmm, ok. If you'd like to make a PR reverting #499, and we can release a patch release fixing this breakage.

We'll then release #499 again but inside 4.0.0. /cc @Daio-io

[keithamus]

Also @tusbar - if you get a PR done ASAP I can cut a release today