Doug
Reputation: 1515
Generate diff JSON
I'm trying to create a function that will do a deep comparison of two JSON objects (objectA vs. objectB). And then generate a unique JSON object that only has the node tree to different data values.
My idea was to ship parts of the JSON into a recursive function, coupled with an array that held the data path. But when I run the code as I have it written, I am getting extra elements in my path array.
The end result ideally will provide a path like:
[ "level1c", "level2b", "level3c" ]
but unfortunately I am getting:
[ "level1a", "level1b", "level1c", "level2b", "level3c" ]
Once, I had a solid data path, then I was going to take that to build a new JSON object that only includes the nodes that differ.
function compareJSON( primary, secondary ){
function diffJSON( primary, secondary, path ){
var p = path.slice(); // copy array
var keys = Object.keys( secondary );
var sVal;
var pVal;
for( var i=0, x=keys.length; i<x; i++ ){
sVal = secondary[keys[i]];
pVal = primary[keys[i]];
if( sVal !== pVal ){
p.push( keys[i] );
if( typeof sVal === 'object' && !Array.isArray( sVal ) ){
diffJSON( pVal, sVal, p );
}else{
if( Array.isArray( sVal ) ){
compareArray( sVal, pVal, p );
}else{
updateResult( sVal, p );
}// END if( !Array.isArray() )
}// END if( typeof sVal === 'object' ... )
}// END if( sVal !== pVal )
}// END for loop
function compareArray( arr, arr2, path ){
// compare arrays
}
function updateResult( data, path ){
console.log( data, path );
}// END function updateResult()
}// END function diffJSON()
diffJSON( primary, secondary, [] );
}// END function compareJSON()
Additional info:
- I know that objectA and objectB are both structured the same; wherein objectB will only ever be a modification of the data in objectA.
- Looking for a less than ES6 solution (old browser support fun).
- The primary question is how do I capture the right node path towards differing data; any tips/tricks/comments on how to improve the core code is welcome but not really the answer.
Here's the code in practice, it prints out into the console a value that's found to be different in json2 (compared to json1) and the associated path array:
'use strict';
function compareJSON( primary, secondary ){
function diffJSON( primary, secondary, path ){
var p = path.slice(); // copy array
var keys = Object.keys( secondary );
var sVal;
var pVal;
for( var i=0, x=keys.length; i<x; i++ ){
sVal = secondary[keys[i]];
pVal = primary[keys[i]];
if( sVal !== pVal ){
p.push( keys[i] );
if( typeof sVal === 'object' && !Array.isArray( sVal ) ){
diffJSON( pVal, sVal, p );
}else{
if( Array.isArray( sVal ) ){
compareArray( sVal, pVal, p );
}else{
updateResult( sVal, p );
}// END if( !Array.isArray() )
}// END if( typeof sVal === 'object' ... )
}// END if( sVal !== pVal )
}// END for loop
function compareArray( arr, arr2, path ){
var match = true;
for( var i=0, x=arr.length; i<x; i++ ){
if( arr[i] !== arr2[i] ){
match = false;
}
}
if( !match ){
updateResult( arr, path );
}
}
function updateResult( data, path ){
console.log( data, path );
}// END function updateResult()
}// END function diffJSON()
diffJSON( primary, secondary, [] );
}// END function compareJSON()
var json1 = {
level1a : {
level2a : {
level3a : 'apple',
level3b : ['happy', 'happy', 'joy', 'joy'],
level3c : {
level4a : 'sleep'
},
level3d : true
},
level2b : 'music',
level2c : {
level3a : 'future',
level3b : false,
level3c : ['bear', 'camel', 'elephant']
}
},
level1b : {
level2a : 'jeopardy',
level2b : 10200,
level2c : true,
level2d : {
level3a : 'aliens',
level3b : 'weekend'
}
},
level1c : {
level2a : 'fiber',
level2b : [1, 2, 4, 5, 6]
},
level1d : ['apple', 'cat', 'baby'],
level1e : true,
level1f : {
level2a : false,
level2b : true,
level2c : {
level3a : 'naruto',
level3b : 123,
level3c : 'test',
level3d : 'this',
level3e : 'thing'
},
level2d : true
}
};
var json2 = {
level1a : {
level2a : {
level3a : 'apple',
level3b : ['happy', 'happy', 'joy', 'joy'],
level3c : {
level4a : 'sleep'
},
level3d : true
},
level2b : 'music',
level2c : {
level3a : 'future',
level3b : false,
level3c : ['bear', 'camel', 'elephant', 'lion']
}
},
level1b : {
level2a : 'jeopardy',
level2b : 10200,
level2c : true,
level2d : {
level3a : 'ancient',
level3b : 'weekend'
}
},
level1c : {
level2a : 'fiber',
level2b : [1, 2, 4, 5, 6]
},
level1d : ['apple', 'cat', 'baby'],
level1e : true,
level1f : {
level2a : false,
level2b : true,
level2c : {
level3a : 'naruto',
level3b : 123,
level3c : 'spicy',
level3d : 'this',
level3e : 'thing'
},
level2d : true
}
};
compareJSON( json1, json2 );Thanks for your time and support :)
Upvotes: 2
Views: 1203
Answers (1)
Shyam Babu
Reputation: 1079
I've modified your code a little bit to split the variable that hold the path and array that hold all diffs.
I am assuming both structure are equivalent, otherwise you would need to do an intersect and diff on keys of a and b, print diffs separately and loop on intersect.
I am using Object.prototype.toString so that in future you might add more cases (switch case friendly if you wanna go that route) and to reduce the checks.
//if you want you pass allDiffs and path here and enhance this function to print array positional diff also
var isEqualArrays = function compareArray( arr1, arr2 ){
if(arr1.length !== arr2.length) return false;
var match = true;
for( var i=0, x=arr1.length; i<x; i++ ){
if( arr1[i] !== arr2[i] ){
match = false;
}
}
return match;
}
var toString = Object.prototype.toString;
function compare (a, b, allDiffs, previousPath) {
var akeys = Object.keys(a);
for (key of akeys) {
var currentPath = previousPath.concat(key);
var typeOfa = toString.call(a[key]);
var typeOfb = toString.call(b[key]);
if(typeOfa !== typeOfb) {
allDiffs.push({path: currentPath, values: [a[key], b[key]] })
continue
}
if(typeOfa === '[object Array]') {
if(!isEqualArrays(a[key], b[key])){//remove this if , if you want enhance route
allDiffs.push({path: currentPath, values: [a[key], b[key]] })
}
continue;
}
if(typeOfa === '[object Object]') {
compare(a[key], b[key], allDiffs, currentPath)
continue
}
if(a[key] !== b[key]) {
allDiffs.push({path: currentPath, values: [a[key], b[key]] })
}
}
return allDiffs
}
var json1 = {
level1a : {
level2a : {
level3a : 'apple',
level3b : ['happy', 'happy', 'joy', 'joy'],
level3c : {
level4a : 'sleep'
},
level3d : true
},
level2b : 'music',
level2c : {
level3a : 'future',
level3b : false,
level3c : ['bear', 'camel', 'elephant']
}
},
level1b : {
level2a : 'jeopardy',
level2b : 10200,
level2c : true,
level2d : {
level3a : 'aliens',
level3b : 'weekend'
}
},
level1c : {
level2a : 'fiber',
level2b : [1, 2, 4, 5, 6]
},
level1d : ['apple', 'cat', 'baby'],
level1e : true,
level1f : {
level2a : false,
level2b : true,
level2c : {
level3a : 'naruto',
level3b : 123,
level3c : 'test',
level3d : 'this',
level3e : 'thing'
},
level2d : true
}
};
var json2 = {
level1a : {
level2a : {
level3a : 'apple',
level3b : ['happy', 'happy', 'joy', 'joy'],
level3c : {
level4a : 'sleep'
},
level3d : true
},
level2b : 'music',
level2c : {
level3a : 'future',
level3b : false,
level3c : ['bear', 'camel', 'elephant', 'lion']
}
},
level1b : {
level2a : 'jeopardy',
level2b : 10200,
level2c : true,
level2d : {
level3a : 'ancient',
level3b : 'weekend'
}
},
level1c : {
level2a : 'fiber',
level2b : [1, 2, 4, 5, 6]
},
level1d : ['apple', 'cat', 'baby'],
level1e : true,
level1f : {
level2a : false,
level2b : true,
level2c : {
level3a : 'naruto',
level3b : 123,
level3c : 'spicy',
level3d : 'this',
level3e : 'thing'
},
level2d : true
}
};
console.log(compare(json1, json2, [], []))Upvotes: 1
Related Questions
- Getting the difference between 2 JSON objects
- Simple git-like diff of two JSONs in javascript
- How can I detect differences of JSON in javascript?
- Javascript JSON comparison/diff?
- JSON diff of large JSON data, finding some JSON as a subset of another JSON
- Is there an established representation for the difference between two JSONs?
- Getting a diff of two json-objects
- How to push diffs of data (possibly JSON) to a server?
- Compare Two Json object's value, Find the Difference of objects's value and ouptut to new Json
- Diff arrays containing JSON with Node.js