JarCastingJSON structural diff
Does exactly what you think it does:
Installation
npm install -g json-diff
Contribution policy
-
This project is maintained thanks to your contributions! Please send pull requests.
-
I will merge any pull request that adds something useful, does not break existing things, has reasonable code quality and provides/updates tests where appropriate.
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Anyone who gets a significant pull request merged gets commit access to the repository.
Usage
Simple:
json-diff a.json b.json
Detailed:
% json-diff --help
Usage: json-diff [-vjCk] first.json second.json
Arguments:
first.json Old file
second.json New file
General options:
-v, --verbose Output progress info
-C, --[no-]color Colored output
-j, --raw-json Display raw JSON encoding of the diff
-k, --keys-only Compare only the keys, ignore the differences in values
-h, --help Display this usage information
In javascript (ES5):
var jsonDiff = require('json-diff')
console.log(jsonDiff.diffString({ foo: 'bar' }, { foo: 'baz' }));
// Output:
// {
// - foo: "bar"
// + foo: "baz"
// }
console.log(jsonDiff.diff({ foo: 'bar' }, { foo: 'baz' }));
// Output:
// { foo: { __old: 'bar', __new: 'baz' } }
In javascript (ES6+):
import { diffString, diff } from 'json-diff';
console.log(diffString({ foo: 'bar' }, { foo: 'baz' }));
console.log(diff({ foo: 'bar' }, { foo: 'baz' }));
Features
- colorized, diff-like output
- fuzzy matching of modified array elements (when array elements are object hierarchies)
- compare only the json structure (keys), ignoring the values
- reasonable test coverage (far from 100%, though)
Tests
Run:
npm test
Test coverage report:
npm run-script cov
Output:
colorize
✓ should return ' <value>' for a scalar value
✓ should return '-<old value>', '+<new value>' for a scalar diff
✓ should return '-<removed key>: <removed value>' for an object diff with a removed key
✓ should return '+<added key>: <added value>' for an object diff with an added key
✓ should return '+<added key>: <added stringified value>' for an object diff with an added key and a non-scalar value
✓ should return ' <modified key>: <colorized diff>' for an object diff with a modified key
✓ should return '+<inserted item>' for an array diff
✓ should return '-<deleted item>' for an array diff
diff
with simple scalar values
✓ should return undefined for two identical numbers
✓ should return undefined for two identical strings
✓ should return { __old: <old value>, __new: <new value> } object for two different numbers
with objects
✓ should return undefined for two objects with identical contents
✓ should return undefined for two object hierarchies with identical contents
✓ should return { <key>__deleted: <old value> } when the second object is missing a key
✓ should return { <key>__added: <new value> } when the first object is missing a key
✓ should return { <key>: { __old: <old value>, __new: <new value> } } for two objects with diffent scalar values for a key
✓ should return { <key>: <diff> } with a recursive diff for two objects with diffent values for a key
with arrays of scalars
✓ should return undefined for two arrays with identical contents
✓ should return [..., ['-', <removed item>], ...] for two arrays when the second array is missing a value
✓ should return [..., ['+', <added item>], ...] for two arrays when the second one has an extra value
✓ should return [..., ['+', <added item>]] for two arrays when the second one has an extra value at the end (edge case test)
with arrays of objects
✓ should return undefined for two arrays with identical contents
✓ should return [..., ['-', <removed item>], ...] for two arrays when the second array is missing a value
✓ should return [..., ['+', <added item>], ...] for two arrays when the second array has an extra value
✓ should return [..., ['~', <diff>], ...] for two arrays when an item has been modified (note: involves a crazy heuristic)
✔ 25 tests complete (12ms)
License
© Andrey Tarantsov. Distributed under the MIT license.