JSON structural diff
Does exactly what you think it does:
Installation
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:
Detailed:
% json-diff --help
Usage: json-diff [-vCjfonskKp] 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
-f, --full Include the equal sections of the document, not just the deltas
--max-elisions COUNT Max number of ...s to show in a row in "deltas" mode (before
collapsing them)
-o, --output-keys KEYS Always print this comma separated keys, with their value, if they are
part of an object with any diff
-x, --exclude-keys KEYS Exclude these comma separated keys from comparison on both files
-n, --output-new-only Output only the updated and new key/value pairs (without marking them as
such). If you need only the diffs from the old file, just exchange the
first and second json.
-s, --sort Sort primitive values in arrays before comparing
-k, --keys-only Compare only the keys, ignore the differences in values
-K, --keep-unchanged-values Instead of omitting values that are equal, output them as they are
-p, --precision DECIMALS Round all floating point numbers to this number of decimal places prior
to comparison
-h, --help Display this usage informationIn javascript (ES5):
var jsonDiff = require('json-diff');
console.log(jsonDiff.diffString({ foo: 'bar' }, { foo: 'baz' }));
// Output:
// {
// - foo: "bar"
// + foo: "baz"
// }
// As above, but without console colors
console.log(jsonDiff.diffString({ foo: 'bar' }, { foo: 'baz' }, { color: false }));
// Raw output:
console.log(jsonDiff.diff({ foo: 'bar', b: 3 }, { foo: 'baz', b: 3 }));
// Output:
// { foo: { __old: 'bar', __new: 'baz' } }
// Passing in the "full" option:
console.log(jsonDiff.diff({ foo: 'bar', b: 3 }, { foo: 'baz', b: 3 }, { full: true }));
// Output:
// { foo: { __old: 'bar', __new: 'baz' }, b: 3 }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)
- "keysOnly" option to compare only the json structure (keys), ignoring the values
- "full" option to output the entire json tree, not just the deltas
- "outputKeys" option to always output the given keys for an object that has differences
- reasonable test coverage (far from 100%, though)
Output Language in Raw-json mode ("full" mode)
ARRAYS
Unless two arrays are equal, all array elements are transformed into 2-tuple arrays:
- The first element is a one character string denoting the equality ('+', '-', '~', ' ')
- The second element is the old (-), new (+), altered sub-object (~), or unchanged (' ') value
json-diff.js --full --raw-json <(echo '[1,7,3]') <(echo '[1,2,3]')
[ [ " ", 1 ], [ "-", 7 ], [ "+", 2 ], [ " ", 3 ] ] json-diff.js --full --raw-json <(echo '[1,["a","b"],4]') <(echo '[1,["a","c"],4]')
[ [ " ", 1 ], [ "~", [ [ " ", "a" ], [ "-", "b" ], [ "+", "c" ] ] ], [ " ", 4 ] ]
- If two arrays are equal, they are left as is.
OBJECTS
Object property values:
- If equal, they are left as is
- Unequal scalar values are replaced by an object containing the old and new value:
json-diff.js --full --raw-json <(echo '{"a":4}') <(echo '{"a":5}')
{ "a": { "__old": 4, "__new": 5 } }
- Unequal arrays and objects are replaced by their diff:
json-diff.js --full --raw-json <(echo '{"a":[4,5]}') <(echo '{"a":[4,6]}')
{ "a": [ [ " ", 4 ], [ "-", 5 ], [ "+", 6 ] ] }Object property keys:
- Object keys that are deleted or added between two objects are marked as such:
json-diff.js --full --raw-json <(echo '{"a":[4,5]}') <(echo '{"b":[4,5]}')
{ "a__deleted": [ 4, 5 ], "b__added": [ 4, 5 ] }
json-diff.js --full --raw-json <(echo '{"a":[4,5]}') <(echo '{"b":[4,6]}')
{ "a__deleted": [ 4, 5 ], "b__added": [ 4, 6 ] }Non-full mode
- In regular, delta-only (non-"full") mode, equal properties and values are omitted:
json-diff.js --raw-json <(echo '{"a":4, "b":6}') <(echo '{"a":5,"b":6}')
{ "a": { "__old": 4, "__new": 5 } }
- Equal array elements are represented by a one-tuple containing only a space " ":
json-diff.js --raw-json <(echo '[1,7,3]') <(echo '[1,2,3]')
[ [ " " ], [ "-", 7 ], [ "+", 2 ], [ " " ] ]Tests
Run:
Output:
Open to View Test Output 🔽
[email protected] test
coffee -c test; mocha test/*.js
colorizeToArray
✔ should return ' ' for a scalar value
✔ should return ' ' for 'null' value
✔ should return ' ' for 'false' value
✔ should return '-', '+' for a scalar diff
✔ should return '-', '+' for 'null' and 'false' diff
✔ should return '-: ' for an object diff with a removed key
✔ should return '+: ' for an object diff with an added key
✔ should return '+: ' for an object diff with an added key with 'null' value
✔ should return '+: ' for an object diff with an added key with 'false' value
✔ should return '+: ' for an object diff with an added key and a non-scalar value
✔ should return ' : ' for an object diff with a modified key
✔ should return '+' for an array diff
✔ should return '-' for an array diff
✔ should handle an array diff with subobject diff
✔ should collapse long sequences of identical subobjects into one '...'
colorize
✔ should return a string with ANSI escapes
✔ should return a string without ANSI escapes on { color: false }
diff
with simple scalar values
✔ should return undefined for two identical numbers
✔ should return undefined for two identical strings
✔ should return { __old: , __new: } object for two different numbers
with objects
✔ should return undefined for two empty objects
✔ should return undefined for two objects with identical contents
✔ should return undefined for two object hierarchies with identical contents
✔ should return { __deleted: } when the second object is missing a key
✔ should return { __added: } when the first object is missing a key
✔ should return { : { __old: , __new: } } for two objects with different scalar values for a key
✔ should return { : } with a recursive diff for two objects with different values for a key
with arrays of scalars
✔ should return undefined for two arrays with identical contents
✔ should return [..., ['-', ], ...] for two arrays when the second array is missing a value
✔ should return [..., ['+', ], ...] for two arrays when the second one has an extra value
✔ should return [..., ['+', ]] 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 undefined for two arrays with identical, empty object contents
✔ should return undefined for two arrays with identical, empty array contents
✔ should return undefined for two arrays with identical array contents including 'null'
✔ should return undefined for two arrays with identical, repeated contents
✔ should return [..., ['-', ], ...] for two arrays when the second array is missing a value
✔ should return [..., ['+', ], ...] for two arrays when the second array has an extra value
✔ should return [['+', ], ..., ['+', ]] for two arrays containing objects of 3 or more properties when the second array has extra values (fixes issue #57)
✔ should return [..., ['+', ], ...] for two arrays when the second array has a new but nearly identical object added
✔ should return [..., ['~', ], ...] for two arrays when an item has been modified
with reported bugs
✔ should handle type mismatch during scalarize
✔ should handle mixed scalars and non-scalars in scalarize
diff({sort: true})
with arrays
✔ should return undefined for two arrays with the same contents in different order
diff({keepUnchangedValues: true})
with nested object
✔ should return partial object with modified and unmodified elements in the edited scope
diff({full: true})
with simple scalar values
✔ should return the number for two identical numbers
✔ should return the string for two identical strings
✔ should return { __old: , __new: } object for two different numbers
with objects
✔ should return an empty object for two empty objects
✔ should return the object for two objects with identical contents
✔ should return the object for two object hierarchies with identical contents
✔ should return { __deleted: , } when the second object is missing a key
✔ should return { __added: , } when the first object is missing a key
✔ should return { : { __old: , __new: } } for two objects with different scalar values for a key
✔ should return { : , } with a recursive diff for two objects with different values for a key
✔ should return { : , } with a recursive diff for two objects with different values for a key
with arrays of scalars
✔ should return an array showing no changes for any element for two arrays with identical contents
✔ should return [[' ', ], ['-', ], [' ', ]] for two arrays when the second array is missing a value
✔ should return [' ', ], ['+', ], [' ', ]] for two arrays when the second one has an extra value
✔ should return [' ', s], ['+', ]] for two arrays when the second one has an extra value at the end (edge case test)
with arrays of objects
✔ should return an array of unchanged elements for two arrays with identical contents
✔ should return an array with an unchanged element for two arrays with identical, empty object contents
✔ should return an array with an unchanged element for two arrays with identical, empty array contents
✔ should return an array of unchanged elements for two arrays with identical array contents including 'null'
✔ should return an array of unchanged elements for two arrays with identical, repeated contents
✔ should return [[' ', ], ['-', ], [' ', ]] for two arrays when the second array is missing a value
✔ should return [[' ', ], ['+', ], [' ', ]] for two arrays when the second array has an extra value
✔ should return [[' ', ], ['+', ], [' ', ]] for two arrays when the second array has a new but nearly identical object added
✔ should return [[' ', ], ['~', ], [' ', ]] for two arrays when an item has been modified
diff({ outputKeys: foo,bar }
✔ should return keys foo and bar although they have no changes
✔ should return keys foo (with addition) and bar (with no changes)
✔ should return keys foo and bar (with addition)
✔ should return nothing as the entire object is equal, no matter that show keys has some of them
✔ should return the keys of an entire object although it has no changes
diff({keysOnly: true})
with simple scalar values
✔ should return undefined for two identical numbers
✔ should return undefined for two identical strings
✔ should return undefined object for two different numbers
with objects
✔ should return undefined for two empty objects
✔ should return undefined for two objects with identical contents
✔ should return undefined for two object hierarchies with identical contents
✔ should return { __deleted: } when the second object is missing a key
✔ should return { __added: } when the first object is missing a key
✔ should return undefined for two objects with different scalar values for a key
✔ should return undefined with a recursive diff for two objects with different values for a key
✔ should return { : } with a recursive diff when second object is missing a key and two objects with different values for a key
with arrays of scalars
✔ should return undefined for two arrays with identical contents
✔ should return undefined for two arrays with when an item has been modified
✔ should return [..., ['-', ], ...] for two arrays when the second array is missing a value
✔ should return [..., ['+', ], ...] for two arrays when the second one has an extra value
✔ should return [..., ['+', ]] 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 undefined for two arrays with identical, empty object contents
✔ should return undefined for two arrays with identical, empty array contents
✔ should return undefined for two arrays with identical, repeated contents
✔ should return [..., ['-', ], ...] for two arrays when the second array is missing a value
✔ should return [..., ['+', ], ...] for two arrays when the second array has an extra value
✔ should return [..., ['~', ], ...] for two arrays when an item has been modified
diffString
✔ should produce the expected result for the example JSON files
✔ should produce the expected result for the example JSON files with precision set to 1
✔ should produce the expected colored result for the example JSON files
✔ return an empty string when no diff found
diff({ outputNewOnly: true }
✔ should return only new diffs (added)
✔ should return only new diffs (changed)
✔ should return only new diffs (deleted)
✔ should return only old diffs - exchanged first and second json (added)
✔ should return only old diffs - exchanged first and second json (changed)
✔ should return only old diffs - exchanged first and second json (deleted)
107 passing (74ms)
Change Log
- 1.0.6 Comment out another debugging output.
- 1.0.5 Comment out debugging output(!)
- 1.0.4 Fix typo that broke -o/--output-keys
- 1.0.3 Change from cli-color to colors to reduce package size.
- 1.0.2 Add colorize and colorizeToCallback to module exports (Fix bug #103)
- 1.0.1 Bug fixes: Properly compare date objects; properly exclude keys with -x; improve README readability.
- 1.0.0 Properly distinguish list elements with identical strings of different types e.g.
["true"] vs [true], ["0"] vs [0] (enabled by switching to a new difflib)
- 0.10.0 Add --exclude-keys
- 0.9.1 Fix bug #88
- 0.9.0 Add --output-new-only option
- 0.8.0 Add --keep-unchanged-values option
- 0.7.4 Fix bug #76
- 0.7.3 Revert use of ?? operator in 0.7.2 (which caused a breaking change)
- 0.7.2 Add --maxElisions and --precision options.
- 0.7.1 Add --output-keys option.
- 0.7.0 Add --sort option.
- 0.6.3 Fix ticket #68.
- 0.6.2 Provide examples of setting mode from code.
- 0.6.1 Return exit code 0. Update cli-color to the latest version.
- 0.6.0 Convert project code to ES6.
- 0.5.5 Fix bug in scalarize fuzzy compare logic.
- 0.4.0 Add --keys-only feature.
License
© Andrey Tarantsov. Distributed under the MIT license.
