updating fields matching condition under not nice path

I need very often update conditionally some fields in subtree to which leads ugly path. I kinda can solve it, but it’s very ugly solution, I’d like to know if there is smth better.

Sample input:

{
  "very": {
    "un-fortunate": {
      "p-a-t-h": {
        "first": {
          "veryDeepSubTree": {},
          "someValue": 1
        },
        "second": {
          "veryDeepSubTree": {},
          "someValue": 2
        },
        "third": {
          "veryDeepSubTree": {},
          "someValue": 3
        }
      }
    }
  }
}

desired output: say that I would like to add 10 to someValue. Suppose that I cannot use recursive descent, for example I want to update only odd someValue.

I can write solution like this:

jq '.very|=(.["un-fortunate"]|=(.["p-a-t-h"] |=(  . as $root| reduce keys[] as $k ({}; . + {($k): ($root|.[$k]|.someValue|=(.+10))})      )))'

but it’s hard to read and write (matching brackets)…

explained motivation, based on my (mis?)understanding:

• iiuc I need to bracket every non-trivial right operand of |= , especially if there are more of them, otherwise it does not compile
• I cannot express longer path than just one field at a time, if path is sufficiently ugly
• there isn’t other way(maybe except foreach, which I cannot understand) to update all items of object, than using reduce to copy all into new updating value, and update each part in update clause of reduce command

questions:

• is there some better way of expressing unfortunate path from tree root?
• can I express it somehow easier than via using this reduce over keys, and putting field update logic into accumulator part of reduce command?
• if you are writing commands into shell, how do you do it so that you can easily edit it + it’s readable?

>Solution :

You could use the array value iterator [] in combination with the (arithmetic) update-assignment operator |=.

To update all someValues:

.very."un-fortunate"."p-a-t-h"[].someValue |= . + 10

or

.very."un-fortunate"."p-a-t-h"[].someValue += 10

To update only someValues which are odd, filter through select and don’t forget to parenthesize the LHS):

(.very."un-fortunate"."p-a-t-h"[].someValue | select(. % 2 != 0)) += 10

Output:

{
  "very": {
    "un-fortunate": {
      "p-a-t-h": {
        "first": {
          "veryDeepSubTree": {},
          "someValue": 11
        },
        "second": {
          "veryDeepSubTree": {},
          "someValue": 2
        },
        "third": {
          "veryDeepSubTree": {},
          "someValue": 13
        }
      }
    }
  }
}

But even recursive descent would work, you just have to make sure to only select the correct values:

(.. | objects | .someValue | values | select(. % 2 != 0)) += 10

or

(.. | .someValue? | values | select(. % 2 != 0)) += 10

Output is identical to above.