Compare-Json-Arrays-In-Files

Note: ⚠️ If you're interested in Software Bill of Materials, you might also look into Bompare

Description

Compares the contents of two JSON files as provided in the command line.

Output is three json files, containing common elements and deltas:

• commonElements.json, contains the elements common to both file in the left as well as the one in the right
• elementsInLeftOnly.json: contains the elements which are only found in the left file
• elementsInRightOnly.json: contains the elements which are only found in the right file

Note: contents of these output files is sorted as follows:

• keys in each element of the array are sorted alphabetically
• elements in the array are sorted by their string representation.

Why was this needed?

Unlike other tools that provide a diff-like view in one file, and instead of comparing the contents of files side-by-side using a diff text tool, Compare-Json-Arrays-In-Files provides a clear overview of the common parts and deltas (to three output files), taking into consideration that the order of elements to be compared may be different between files.

Thus, if the left file would contain:

[
  {"letter": "A", "digit": "1"},
  {"letter": "B", "digit": "2"},
  {"letter": "C", "digit": "3"}
]

and the right one would contain:

[
  {"digit": "1", "letter": "A"},
  {"digit": "3", "letter": "C"},
  {"letter": "B", "digit": "2"}
]

then Compare-Json-Arrays-In-Files would conclude that the files have the same JSON contents.

It outputs at one glance, in the console output:

• a comparison of the number of elements read from each of the input files
• a high-level comparison based on the contents, i.e. #elements that are common, #elements that are found only in the left file, #elements were only found in the right file.
• names of the output files This overview is very useful especially when the two files contain hundreds or more elements.

Status

v1.0.0, see CHANGELOG.md

Limitations

• currently only supporting flat JSON objects (no nested structures)

Prerequisites

• you should have Node installed (this script was tested with node v12.2.0)
• you should have yarn installed (we used version v1.19.0)

How to run

yarn compareJsonFiles [options] <leftFile> <rightFile>

Mandatory arguments:

Arguments	Functionality
leftFile	Left input .json filename used in comparison
rightFile	Right input .json filename used in comparison

Supported options:

Flag	Alias	Functionality
--verbose		Verbose output of commands and errors
--help	-h	Help
--version	-v	Version

Sample usage

yarn compareJsonFiles ./testData/fileWithABC.json ./testData/fileWithBCD.json --verbose

Technology stack

• Javascript
• This software is intended to be used standalone, as a command-line tool

How to build

Get the sources locally; in a command line, go to the root folder of this project and execute:

yarn install

How to test

yarn test

or, to get the coverage:

yarn coverage

How to do static analysis of code

Automatically enabled: standard

yarn lint

Owners

See CODEOWNERS

Maintainers

See MAINTAINERS.md

Contributing

See CONTRIBUTING.md

License

See LICENSE.md

Keywords

• json arrays comparer
• json arrays delta