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Java4you
Java4you

Reputation: 656

Update matched key values in two JavaScript objects

My requirement is compare two objects and copy updated values into first object from second object. Ex : 

$scope.obj1={"id" : 1, "name" : "java"}
$scope.obj2={"id" : 1, "name" : "java4you", "gender" : "male"}

compare(destination, bj1, obj2);

Destination variable Output: 

{"id" : 1, "name" : "java4you"}

The above two objects contains same keys but values are different. I have to compare obj1 and obj2 and update with matched obj2 values

Upvotes: 3

Views: 2798

Answers (5)

omostan
omostan

Reputation: 881

I had to update @Bharadwaj answer for it to work for me.
for (... in ...) statements must be filtered with an if statement

    var obj1={"id" : 1, "name" : "java"},
        obj2={"id" : 1, "name" : "java4you", "gender" : "male"};

    function compare(obj1, obj2) {
      let obj = {};
      for(let k in obj1) {
         if(obj1[k] !== obj2[k]) {
           obj = Object.assign({}, obj1, obj1[k] = obj2[k]);
         }
         
      }
      return obj;
    }

Upvotes: 0

Hassan Imam
Hassan Imam

Reputation: 22564

You can create a copy of obj1 using Object.assign() in a new variable, destination and iterate through each key of obj2 using Object.keys() and array#forEach and check if key exists in destination, in case it exists, update the value in destination from the value of obj2

var obj1={"id" : 1, "name" : "java"},
    obj2={"id" : 1, "name" : "java4you", "gender" : "male"}

var updateObjectValue = (obj1, obj2) => {
  var destination = Object.assign({}, obj1);
  Object.keys(obj2).forEach(k => {
    if(k in destination) {
      destination[k] = obj2[k];
    }
  });
  return destination;
}
console.log(updateObjectValue(obj1, obj2));

Upvotes: 1

Bharadwaj
Bharadwaj

Reputation: 2553

Try this,

function compare(obj1, obj2)
{
    let obj = {};
    for(let k in obj1)
    {
         obj[k] = obj2[k];
     }
    return obj;
}

Usage should be like,

var destination = compare(obj1,obj2);

Upvotes: 0

Sudi065
Sudi065

Reputation: 467

Using Angularjs, you can use .equal to compare and get the result, I don't see what is not working or providing your code will only gets you the answers.

$scope.result = angular.equals($scope.obj1, $scope.obj2);
if($scope.result === true){    
$scope.obj1 = $scope.obj2;
}

Upvotes: 0

flx
flx

Reputation: 1578

Without actually referring to methods that can be used in angularJs, You can try this:

function compare(o1, o2) {
  var biggest = o1;
  
  if (Object.keys(o2).length > Object.keys(o1).length) {
    biggest = o2;
  }

	for (let key in biggest) {
  	if (!biggest.hasOwnProperty(key)) continue;
    
    if (o1[key] != o2[key]) {
    	console.info("Difference in '"+ key +"': "+ o1[key] +" <> "+ o2[key]);
    }
	}
}

var $scope = {};

$scope.obj1 = {"id" : 1, "name" : "java"};
$scope.obj2 = {"id" : 1, "name" : "java4you", "gender" : "male"};

compare($scope.obj1, $scope.obj2);

But be careful using this, since it has many possible cases to fail.

Upvotes: 0

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