Multi-line scripts in kibana's json input

[geo909]

Dear all,

I'm trying to understand how to use scripted fields in Kibana's JSON input, and I am having a hard time with multi-line scripts.

For example, I have a line visualization and I want to define a metric on the Y-Axis, with a new variable which is the difference of two existing variables. Using an inline expression, I can put the following in the json input and it works as expected, giving me a visualization of the difference of these fields:

{
  "script" : {
    "source" : "doc['reservationAmount'].value - doc['cancellation.finalRefundAmount'].value",
    "lang" : "painless"
  }
}

However, I sometimes want to use more complicated, multi-line scripts, so I would prefer to use the syntax with triple quotation marks. I would expect that the following would be equivalent to the above, but it doesn't work, giving me an error :

{
  "script" : {
    "lang" : "painless",
    "source" : """
    return doc['reservationAmount'].value - doc['cancellation.finalRefundAmount'].value
    """
}
}

Could somebody explain why the second syntax doesn't work? Can I adapt it in order to work?

Please bare in mind that 1) this is just a demonstration example, in general I would like to know how to use the multi-line syntax in order to create more complicated scripts and 2) I know how to define scripted fields in kibana, but I don't want to do that for scripted fields that may be used just once in a visualization.

Thank you in advance

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