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@oscherler
Last active April 6, 2023 10:03
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Diff JSON in Git using gron

jsondiff: diff JSON in Git using gron

gron is an incredible tool that makes JSON greppable. But it also makes it diffable, which is great if you have JSON files in Git.

To use gron to diff JSON in Git, save the json-diff script below and make it executable. Then add a difftool as shown in gitconfig, and optionally create an alias to invoke it more easily. Then try it:

git init
echo '{"foo":42,"bar":"hello"}' > foo.json
git add foo.json && git commit -m 'Initial commit.'
echo '{"foo":43,"bar":"hello"}' > foo.json
git jdiff

will give you:

--- a/foo.json
+++ b/foo.json
@@ -1,3 +1,3 @@
 json = {};
 json.bar = "hello";
-json.foo = 42;
+json.foo = 43;
[difftool "jsondiff"]
cmd = "/path/to/json-diff $LOCAL $REMOTE"
[alias]
jdiff = difftool -t jsondiff -y
#!/bin/zsh
# gron: https://github.com/tomnomnom/gron
GRON=/usr/local/bin/gron
DIFF=/usr/bin/diff
# colordiff: https://www.colordiff.org
COLORDIFF=/usr/bin/colordiff
# use colordiff in interactive mode, diff otherwise
if [ -t 1 ]
then
DIFFER=${COLORDIFF}
else
DIFFER=${DIFF}
fi
LOCAL="$1"
REMOTE="$2"
"${DIFFER}" -u --label "a/$REMOTE" --label "b/$REMOTE" <( "$GRON" < "$LOCAL" ) <( "$GRON" < "$REMOTE" ) | less
@mjaggard
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I'll give it a go. Thanks

@CholoTook
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Thanks for this, exactly what I was looking for!

@lukestanley
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Is this the most simple way to use gron for diffing JSON in git?
On Ubuntu and I was able to apt install gron and add a .gitattributes with this:
*.json diff=gron

and add to .git/config:
[diff "gron"]
textconv=gron

then I think git diff could be used with it. Not sure if I missed a step. Does this help?

@oscherler
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Author

@lukestanley Seems legit, and very simple indeed. My solution is based on writing json-diff first, and only later thinking of using it with git, so that’s why it’s probably more complicated than needed. Thanks for the heads up.

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