Differences between the javascript and C# $append function

[huangshu91]

Hi @mikhail-barg, we noticed an interesting discrepancy in the behavior of the $append function.

According to the documentation regarding singleton arrays when a single item is returned the result will be that single value rather than an array. However if a '[]' is used in the expression then we get an array with a single item.

https://docs.jsonata.org/predicate#singleton-array-and-value-equivalence

For example if we look at the try jsonata playground:

https://try.jsonata.org/OmF3X21ZQ

$ ~> | $ | {"test": ([] ~> $append(test))}|

For this simple transform query we get:

{ "test": [ { "test": "test" } ] }

However it seems when we run this same query through the c# implementation we get this:

{"test": { "test": "test"}}

We've worked around this but it seems to be a bug?

[mikhail-barg]

hi @huangshu91, thanks for reporting this! I've recently found there seem to be a problem with array constructors in my implementation, that causes some corner cases to behave not in accord with original jsonata-js

For example the behavior addressed here is not yet implemented. The thing you reported seem to have a similar source.

I've made a first attempt to address this issue, but the problem seem to be more deep than I've expected, and fixing it will probably require a lot of careful tunings. So I'll need some time to muster enough courage to make a second attempt.