feat: use chaijs/loupe for inspection

[pcorpet]

Fix #1228

Note that for now this is just a quick attempt to explore which diffs are OK in the error messages and which ones we'd like to fix in loupe before merging.

[pcorpet]

+ expected - actual

-expected +0 to be truthy
+expected 0 to be truthy

I think we'd like https://github.com/chaijs/loupe to display 0 instead of +0. Or do you feel this is a good change?

[pcorpet]

      + expected - actual

      -blah: expected Foo{} to not be an instance of Foo
      +blah: expected {} to not be an instance of Foo

I think this one is a good change, please comment if you disagree

[keithamus]

In both of these instances the changes are welcome I think.

[pcorpet]

Alright, thanks for the confirmation. For the next ones, I suggest you just add an emoji on the github comment to say that you're OK with the change or add a new comment if you're not.

[pcorpet]

Using ISO format for printing dates:

      + expected - actual
      -blah: expected 2021-06-09T11:40:15.786Z to be above 2021-06-09T11:40:16.786Z
      +blah: expected Wed, 09 Jun 2021 11:40:15 GMT to be above Wed, 09 Jun 2021 11:40:16 GMT

[pcorpet]

Unquoted complex key in objects:

      + expected - actual

      -expected { foo.bar: 'baz' } to have nested property 'foo.bar'
      +expected { 'foo.bar': 'baz' } to have nested property 'foo.bar'

[pcorpet]

We'll need to fix chaijs/loupe#44 as well

[pcorpet]

A bit more complex: when using prototype properties,

Object.create({tea: 'chai'})

We use to show it as regular properties:

{tea: 'chai'}

We now exclude them which makes it less readable:

[object Object]

What do you think?

[flaambe]

Using ISO format for printing dates:

      + expected - actual
      -blah: expected 2021-06-09T11:40:15.786Z to be above 2021-06-09T11:40:16.786Z
      +blah: expected Wed, 09 Jun 2021 11:40:15 GMT to be above Wed, 09 Jun 2021 11:40:16 GMT

chaijs/loupe#34

[pcorpet]

Typed array:

      + expected - actual

      -Uint8Array[ 1, 2, 3 ]
      +[ 1, 2, 3 ]

[keithamus]

Unquoted complex key in objects:

      + expected - actual



      -expected { foo.bar: 'baz' } to have nested property 'foo.bar'

      +expected { 'foo.bar': 'baz' } to have nested property 'foo.bar'

I think this is a regression. Ideally loupe would give us inspections which are syntactically valid and can be pasted into a REPL with minimal editing. I think loupe should detect if it needs quotes and add them.

[keithamus]

A bit more complex: when using prototype properties,

Object.create({tea: 'chai'})

We use to show it as regular properties:

{tea: 'chai'}

We now exclude them which makes it less readable:

[object Object]

What do you think?

This looks like a regression. I'd expect {} considering it's a prototype property, but we could also special case empty objects to show more info if needed.

[keithamus]

Typed array:

      + expected - actual



      -Uint8Array[ 1, 2, 3 ]

      +[ 1, 2, 3 ]

This is intentional. It is useful to know what typed array class is being inspected. We should update chai here.

[pcorpet]

Another one:

  it('inspect with custom stylize-calling inspect()s', function () {
    chai.use(function (_chai, _) {
      var obj = {
        outer: {
          inspect: function (depth, options) {
            return options.stylize('Object content', 'string');
          }
        }
      };
      expect(_.inspect(obj)).to.equal('{ outer: Object content }');
    });
  });

      + expected - actual

      -{ outer: 'Object content' }
      +{ outer: Object content }

[keithamus]

Another one:

  it('inspect with custom stylize-calling inspect()s', function () {
    chai.use(function (_chai, _) {
      var obj = {
        outer: {
          inspect: function (depth, options) {
            return options.stylize('Object content', 'string');
          }
        }
      };
      expect(_.inspect(obj)).to.equal('{ outer: Object content }');
    });
  });

     + expected - actual

     -{ outer: 'Object content' }
     +{ outer: Object content }

What does nodejs do here? To me the loupe example seems correct but I’d be interested in Nodes output as it has the same API

[pcorpet]

What does nodejs do here? To me the loupe example seems correct but I’d be interested in Nodes output as it has the same API

For reference this is Node's API.

So the test is correct and I should fix the code.

[pcorpet]

To make progress on this, I would now need some reviews on loupe pull requests. @keithamus can you take a look please? https://github.com/chaijs/loupe/pulls

[keithamus]

All fixes on loupe and been merged and published to npm. This should be able to progress now.

[keithamus]

@pcorpet I've also invited you to the chai org as a maintainer for loupe!

[pcorpet]

Thanks for the review, this PR should now be good for review as the tests pass.

[keithamus]

This LGTM but perhaps a second set of eyes would be good. @flaambe as you worked on this before, do you think this looks good?

[keithamus]

I feel like we're losing data here. Perhaps this should be a feature of loupe that if the object has no own-properties then it can inspect the prototype to make it more useful for instances like this?

[keithamus]

This is so much nicer IMO 👌

[flaambe]

LGTM, but I was thinking we are going to replace lib/chai/utils/inspect.js completely?

[keithamus]

I agree that's definitely the ultimate goal here. Merging this PR gets us a lot closer to that though so I'm happy to ship this.

[keithamus]

@pcorpet did you want to try porting this PR to the 4.x branch and we can cut a prerelease to make sure it doesn’t break folks workflow.