Exception on array types

[vicary]

I have initiated the form scope with an empty object {}, one of it's properties are of array type with simple string as items.

When I click on the "Add" button it returns the follow error,

TypeError: Cannot read property 'length' of undefined
    at n.angular.module.directive.link.scope.$watch.scope.appendToArray (/assets/scripts/schema-form.js:1587:27)

Inspecting list and scope.modelArray shows an empty array during form initialize, but list.length loses reference and turns into undefined in line 1587 appendToArray().

[trajano]

The workaround is to have an empty array object in your "default" structure. For example.

{
   "items":[]
}

[trajano]

Without the default array, angular-schema-form will not be able to find it and thus give an undefined when accessing the list variable.

However, my attempts of setting it to [] makes it behave incorrectly, it appears to swap the array with an object whose indices are integers. Not exactly sure which part of the code does that but I did see something about it earlier.

[trajano]

I was thinking something along the lines of scope.model.$watch for {} then initialize it to have the empty arrays. At least that would work for the top level ones, but we need it to work on the arrays within arrays.

[vicary]

Can it be done in render() (line 2157) instead?

[vicary]

I have a general purpose form that works on multiple models, all default values are not applied when I assign an empty object {} into sf-model. I have to make my own creation method for each model at this moment.

[nicklasb]

I am gettings this too now, it seems like a pretty serious problem.

[nicklasb]

Obviously this is not a solution for anyone, but I just realised that angular-schema-form-dynamic-select add-on is not affected by this. I use that everywhere (I am the maintainer), so was basically a mistake that made me encounter this problem.

So if you use that instead of the built-in selects, you are out of the woods on this one. You also get a ton of other features, but I have seen no negative performance impact of the component so far.

[vicary]

The select-external plugin I am currently using also shims the value in some cases, but that's best taken care of in the core.

[nicklasb]

That is correct, of course. I was not suggesting that it shouldn't, it certainly is a serious bug.
That said, it feels like most new users almost immidiately needs the kind of functionality the select add-ons provide anyway, so I'd mention it. (I would also want to call them "plug-ins" instead)