pdiffjson

• pdiffjson is a simple bash script that’s non-obvious and useful enough more developers should have it at their fingertips. It simply combines jq, diff, colordiff, and less to normalize and then diff.
• Not a fancy web UI or a library. Just the simplest and fastest way to get clear, pretty-printed, colored diffs of JSON files on a console. Ignores all irrelevant whitespace and key ordering on collections objects (and ordering on arrays altogether, if you like) only shows you significant differences.
• Works on large files other tools barf on, thanks to jq’s speed.
• Shows context around each difference in a customizable way, thanks to diff.
• Scrollable and searchable output (use space, /), thanks to less.
• Installs quickly anywhere, thanks to npm.
• Extra bonus pjson command that colorizes and pretty-prints only.
• The feature list is longer than the code! 🤯😀

Installation

$ npm install -g pdiffjson

Or copy pjson and pdiffjson to /usr/local/bin by hand! Ensure you have jq and colordiff as well (brew install jq colordiff on Mac).

Usage

$ pdiffjson
Usage: pdiffjson [--sort-arrays] [diff options] file1.json file2.json

Show pretty-printed, colored diff of normalized JSON. Uses less to
paginate the output. Allows a readable diff of any JSON, ignoring all
non-semantic differences of whitespace and key ordering.

Fields of each object are output with the keys in sorted order
prior to calling diff, so insignificant differences of key order
are ignored. The --sort-arrays option also enables recursive sorting
of all array values, so all differences in ordering within arrays
are ignored.

This is a "semi-structural diff", meaning it shows only structural
(semantic) changes but the diff is shown syntactically on JSON output,
which actually makes it more readable and flexible than a true
structural diff.

Works on large files since it relies only on diff and jq.

By default calls diff without arguments, yielding a unified diff. But
it can be helpful to add standard diff arguments to refine the type of
output, such as:
-c (contextual diff),
-C2 (contextual diff with two lines of context), or
-U5 (unified diff with 5 lines of context).

$

Related Work

• Many websites like jsondiff offer JSON diff functionality but offer no command line, don’t work on large files, and are not good for sensitive data.
• jsondiffpatch is a powerful JavaScript library to do JSON diff and patch. Has a command line. Shows a pure structural diff. No semi-structured diff with context.
• diff-json is another useful JavaScript library with a command-line interface. Rather slow on larger (multi-megabyte) files, with no incremental output.
• jd is a powerful Go command line tool. It handles diff and patching. It allows more flexible diffs options on arrays (set and bag). No colored output or diff output options to show more context, as with diff, so the output seems less clear to read.