How to make jq output comma separated when key is absent-CodePudding

I am trying to fetch message field from below json file in comma separated value

[
   {
      "title":"second bad commit",
      "message":"second bad commit"
   },
   {
      "title":"first bad commit",
      "message":"first bad commit",
   }
]

My attempt to do that with jq: jq -r '.message | join(",")'

It keeps throwing following error: jq: error (at <stdin>:0): Cannot index array with string "message"

So, how can I make jq output comma separated when key is absent

CodePudding user response：

Assuming that your data is actually:

[
   {
      "title":"second bad commit",
      "message":"second bad commit"
   },
   {
      "title":"first bad commit",
      "message":"first bad commit"
   }
]

Then you'll need to use map to map each value:

$ jq 'map(.message)'           
[
  "second bad commit",
  "first bad commit"
]

And then just the join pipe:

$ jq 'map(.message) | join(",")'
"second bad commit,first bad commit"

And then adding -r to output the raw value.:

$ jq -r 'map(.message) | join(",")'
second bad commit,first bad commit