Jolt Transform: Single Value can't be added to an Array

Question

I have the following Jolt Spec

 [
  {
    "operation": "shift",
    "spec": {
      "*": {
        "value": "[]"
      }
    }
   },
  {
    "operation": "shift",
    "spec": {
      "*": "values"
    }
   },
  {
    "operation": "default",
    "spec": {
      "values": []
    }
   }
]

For the following Input:

[
  {
    "value": 175
  },
  {
    "value": 160
  }
]

I get the expected result as following:

{
  "values" : [ 175, 160 ]
}

And for the following Input:

[
  {
    "valueNum": 175
  }
]

I again get an expected result as follows:

{
  "values" : [ ]
}

But for the following input :

[
  {
    "value": 175
  }
]

I get the following output

{
  "values" : 175
}

I want to have the values in an array even if there is just one element in it like below:

{
   "values" : [175]
}

Could you please help me fixing my Jolt Spec to get the desired result? Thanks!

Answer 1

Just using a single shift transformation spec as the following one would suffice

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "&s[]"
      }
    }
  }
]

where & is a substitution for the key name(value), and s is a suffix to make the word plural

the demoes on the site http://jolt-demo.appspot.com/ are

Edit : If you need an output based on seperating the keys of the attributes to be value or the others(such as valueNum), then still a single spec like the one below would be sufficient :

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "value": "&s[]",
        "*": "&[]"
      }
    }
  }
]

Answer 2

With the following spec, I was able to achieve all my use cases

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "value": "[]"
      }
    }
   },
  {
    "operation": "shift",
    "spec": {
      "*": "values[]"
    }
   },
  {
    "operation": "default",
    "spec": {
      "values": []
    }
   }
]