How to only merge changed and new data.

[wkleingolden321]

Hi All,
Just installed winmerge (great tool!) and looked around for about an hour, but could not find an answer to my need:

For the attached screen shot:

• Will be merging right to left.
• Want to update the left side when data is changed or completely new, the 2 green checkmarks.
• Do not want data removed on the left side which does not exist on the right, the red X.
• Will always be using Json files and the number of fields will not change.

Example end goal for the merged file;
Key SL-269 is retained.
Key SL-268 is retained.
Key SL-267 is updated with the change on the right.
Key SL-999 is added

I know I can single select which differences to merge, but will have 100s of records and the types of differences will be spread out thru my files.

Is there a way to sort differences so updated and new data is on top?
Is there an option to only merge updated and new data?
Other recommendations on how to approach this need?

[sdottaka]

Unfortunately, WinMerge does not have a function to do the above well.
However, WinMerge comes with a JSON processing tool called the jq command.
I'm not familiar with the jq command, but according to ChatGPT, you can merge the old.json and new.json files and generate a merge.json file by running the following in PowerShell:

& "C:\Program Files\WinMerge\Commands\jq\jq.exe" -s '
  .[0] as $old | .[1] as $new |
  ($old + $new | group_by(.key)) |
  map(
    if length == 1 then
      .[0]
    else
      .[1]
    end
  )
' old.json new.json > merged.json

[old.json]

[
	{
		"key":"SL-269",
		"uniqueId":"48ae",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-23T20:52:54.635-0500",
		"severity":"High",
		"lastActive":"2025-03-19T11:32:00.000-0500"
	},
	{
		"key":"SL-268",
		"uniqueId":"9b7b",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-16T13:23:06.874-0500",
		"severity":"High",
		"lastActive":"2025-03-11T12:52:00.000-0500"
	},
	{
		"key":"SL-267",
		"uniqueId":"9752",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-16T13:23:10.179-0500",
		"severity":"High",
		"lastActive":"2025-03-11T12:52:00.000-0500"
	}
]

[new.json]

[
	{
		"key":"SL-268",
		"uniqueId":"9b7b",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-16T13:23:06.874-0500",
		"severity":"High",
		"lastActive":"2025-03-11T12:52:00.000-0500"
	},
	{
		"key":"SL-267",
		"uniqueId":"9752",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-16T13:23:10.179-0500",
		"severity":"MBO Priority",
		"lastActive":"2025-03-11T12:52:00.000-0500"
	},
	{
		"key":"SL-999",
		"uniqueId":"9752",
		"statusName":"Cancelled",
		"cancelDate":"2025-03-16T13:23:10.179-0500",
		"severity":"High",
		"lastActive":"2025-03-11T12:52:00.000-0500"
	}
]

[wkleingolden321]

Thank you for the help! I will take a look.

[wkleingolden321]

Was able create Python code to address my need.