How to detect differences between two json string in node.js

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I Have Two Json Strings that might have different values at some point of time , and I want to know if is it possible to compare them using JS?

For Instance,
I have these Two Json strings

JavaScript

//First Json
var Json1 = {"Name":"ABC";"Work":"Programmer";State:"123"};

//Second Json
var Json2 = {"Name":"XYZ";"Work":"Engineer";State:"456"};

Here, I want output like below:

Name value changed from 'ABC' to 'XYZ'
Work value changed from 'Programmer' to 'Engineer'
State value changed from '123' to '456'

What I have tried:

Not able to find the solution. Can you please help here?

Posted 6-Jan-17 0:41am

45678910

Updated 23-Nov-19 2:48am

Wendelius

v4

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Comments

Richard MacCutchan 6-Jan-17 6:55am

The obvious way would be to parse each string to an object and then compare the fields.

2 solutions

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Thomas Daniels · Answer 1 · 2017-01-06T01:20:00

Firstly, what you have is not valid JSON. You use semicolons instead of commas. Also in a JSON string, all keys have to be surrounded by quotes (which is not the case in your example).

Your first code step would be to convert the JSON string to an object, using JSON.parse. Then you can use Object.keys to get all keys from the first object, and you can loop over these keys to see the difference in values in the two objects.

JavaScript

var jsonString1 = '{"Name":"ABC","Work":"Programmer","State":"123"}';
var jsonString2 = '{"Name":"XYZ","Work":"Engineer","State":"456"}';

var jsonObject1 = JSON.parse(jsonString1);
var jsonObject2 = JSON.parse(jsonString2);

var keys = Object.keys(jsonObject1);
for (var i = 0; i < keys.length; i++) {
  var key = keys[i];
  if (jsonObject1[key] != jsonObject2[key]) {
    console.log(key + " value changed from '" + jsonObject1[key] + "' to '" + jsonObject2[key] + "'");
  }
}

Member 14665733 · Answer 2 · 2019-11-23T02:48:00

Solution 2

// You Can Use loops to get result exactly as you want

const Json1 = {Name: 'ABC', Work: 'Programmer', State: '123'};
const Json2 = {Name: 'XYZ', Work: 'Engineer', State: '456'};

const obj1Keys = Object.keys(Json1);
const obj1Values = Object.values(Json1);
const obj2Keys = Object.keys(Json2);
const obj2Values = Object.values(Json2);

for ( let i = 0; i < obj1Keys.length; i++ ) {
  for ( let j = 0; j < obj2Keys.length; j++ ) {

    if ( obj1Keys[i] === obj2Keys[j]) {
      if ( obj1Values[i] !== obj2Values[j]) {
          console.log( `${obj1Keys[i]} value changed from
                           '${obj1Values[i]}' to '${obj2Values[j]}'`);
      }
    }
  }
}

Posted 23-Nov-19 2:48am

Member 14665733

Updated 23-Nov-19 2:57am

v4

Comments

Richard Deeming 27-Nov-19 14:54pm

That's the same as solution 1. You've not added anything to the discussion. And by copying someone else's answer, you look like a plagiarist.

Member 14665733 4-Dec-19 22:21pm

Mr. Richard
May be you are a Rote memorizer !
Can you see that the first solution is not giving exactly that answer which one is expected in question description.
And also first solution is not following the current version js or ts lint.
If adding something for discussion is making some confusions then nothing for discussion is better more then adding something for discussion.
if 2 + 2 = 4 then always 2 + 2 = 4.
I am not plagiarist but you look like a blind with perfect eyes.

Richard Deeming 5-Dec-19 6:41am

It may not be exactly the same code, but it is effectively the same suggestion - use Object.keys to get the keys, walk through the list, and compare the values.

I never said you were a plagiarist. I was simply pointing out that you haven't really added anything to the discussion.