Business
Jobs
  • About Us
  • Solutions
    • Job Postings
      Post your job and receive qualified candidates in 48h.
    • Candidate Assessments
      500+ technical and psychological tests, plus anti-fraud.
    • Headhunting
      Tailor-made executive search from start to finish.
    • Payroll + EOR
      Payroll dispersal and EOR across 15+ LATAM countries.
  • Pricing
  • Jobs

0

227
Views
How to return the difference between two Objects having array and return the difference value dynamically

Let's say I have two objects of arrays:

const newObj = {
      description: "abcd",
      type: "anything",
      list: [
        { id: 1, name: "Peter" },
        { id: 2, name: "Cathenna" },
        { id: 3, name: "Chiyo" }
      ]
    }

   const oldObj = {
      description: "wwew",
      type: "anything",
      list: [
        { id: 1, name: "Amara" },
        { id: 2, name: "shinzo" },
        { id: 3, name: "Chiyo" }
      ]
    }

I want to find all the updated data in newObj objects. Ex, description of oldObj is updated to "abcd" in newObj and in list name of two objects has been updated. So, my expected output is:

const extractObjDiff = {
      description: "abcd",
      list: [
        { id: 1, name: "Peter" },
        { id: 2, name: "Cathenna" }
      ]
    }

I have tried below code but it's not working for array list.

function extractObjDiff(newObj, oldObj) {
  var r = {};
  for (var prop in newObj) {
    if (!oldObj.hasOwnProperty(prop)) {
      if (Array.isArray(newObj)) {
        r = newObj;
      } else {
        r[prop] = newObj[prop];
      }
    } else if (newObj[prop] === Object(newObj[prop])) {
      var difference = newObj[prop].length !== oldObj[prop].length ? newObj[prop] : extractObjDiff(newObj[prop], oldObj[prop], []);
      if (Object.keys(difference).length > 0) r[prop] = difference;
    } else if (newObj[prop] !== oldObj[prop]) {
      if (newObj[prop] === undefined)
        r[prop] = 'undefined';
      if (newObj[prop] === null)
        r[prop] = null;
      else if (typeof newObj[prop] === 'function')
        r[prop] = 'function';
      else if (typeof newObj[prop] === 'object')
        r[prop] = 'object'
      else if (Array.isArray(newObj))
        r = newObj;
      else
        r[prop] = newObj[prop];
    }
  }
  return r;
}

about 4 years ago · Juan Pablo Isaza
1 answers
Answer question

0

I have added 2 functions, first one give your expected output and second one give the every changes in the new object.

const newObj = {
  description: "abcd",
  type: "anything",
  list: [
    { id: 1, name: "Peter" },
    { id: 2, name: "Cathenna" },
    { id: 3, name: "Chiyo" }
  ]
};

const oldObj = {
  description: "wwew",
  type: "anything",
  list: [
    { id: 1, name: "Amara" },
    { id: 2, name: "shinzo" },
    { id: 3, name: "Chiyo" }
  ]
};

const findSubChanges = (oldObj, newObj) => {
  let changes=[]
  for (const i in oldObj) {
    if (oldObj[i] instanceof Object) {
      let isChange=false
      for (const j in oldObj[i]){
        if(oldObj[i][j] !== newObj[i][j]){
          isChange=true
          break
        }
      }
      if (isChange){
        changes[i] = newObj[i]
      }
    } else {
      if (oldObj[i] !== newObj[i]) {
        changes[i] = newObj[i];
      }
    }
  }
  return changes
};

const findChanges = (oldObj, newObj) => {
  let changes={}
  for (const i in oldObj) {
    if (oldObj[i] instanceof Object) {
      const change = findSubChanges(oldObj[i], newObj[i]);
      if (change) {
        changes[i] = change
      }
    } else {
      if (oldObj[i] !== newObj[i]) {
        changes[i] = newObj[i];
      }
    }
  }
  return changes
};

const extractObjDiff=findChanges(oldObj, newObj)
console.log(extractObjDiff);

const newObj = {
  description: "abcd",
  type: "anything",
  list: [
    { id: 1, name: "Peter" },
    { id: 2, name: "Cathenna" },
    { id: 3, name: "Chiyo" }
  ]
};

const oldObj = {
  description: "wwew",
  type: "anything",
  list: [
    { id: 1, name: "Amara" },
    { id: 2, name: "shinzo" },
    { id: 3, name: "Chiyo" }
  ]
};


const isArray = (item) => item instanceof Array;
const isJSONObject = (item) =>
  item instanceof Object && !(item instanceof Array);

const findEveryChanges = (oldObj, newObj) => {
  if (
    (isArray(oldObj) && isArray(newObj)) ||
    (isJSONObject(oldObj) && isJSONObject(newObj))
  ) {
    let changes = isArray(oldObj) ? [] : {};
    for (const i in oldObj) {
      if (oldObj[i] instanceof Object) {
        const change = findEveryChanges(oldObj[i], newObj[i]);
        if (change) {
          changes[i] = change;
        }
      } else {
        if (oldObj[i] !== newObj[i]) {
          changes[i] = newObj[i];
        }
      }
    }
    if (Object.keys(changes).length > 0) {
      return changes;
    }
    return;
  }
  if (oldObj !== newObj) {
    return newObj;
  }
  return;
};


console.log(findEveryChanges(oldObj, newObj));

about 4 years ago · Juan Pablo Isaza Report
Answer question
Find remote jobs

Discover the new way to find a job!

Top jobs
Top job categories
Business
Post vacancy Pricing Sales
Legal
Terms and conditions Privacy policy
© 2026 PeakU Inc. All Rights Reserved.
Andres GPT
Show me some job opportunities
There's an error!