Inconsistent Behavior of [] between version 1.7.0 and 1.8.3

Consider the following input:

{
  "singleArray": [{"foo":"bar"}]
}

and JSONata expression: singleArray[]

In version 1.7.0, the evaluated result is

[
  {
    "foo": "bar"
  }
]

but in 1.8.3 it is

[
  [
    {
      "foo": "bar"
    }
  ]
]

Which evaluation is correct and why?

[dreusel]

Shouldn’t changes like this trigger a major version increment, as it breaks applications expecting the previous behavior?

[knolleary]

Just found this issue as I was expecting $map to always return an array. The docs for $map says it returns an Array and doesn’t mention the singleton sequence case.

I found the workaround was to add [] after the $map function - this appears to ensure the result is always an array without causing the double nested array mentioned above:

$map($.payload, function($v) {  {"className":$v.className, "score":$v.score*100, "bbox":$v.bbox}})[]