How to compare two array object but any one of the array object does not having key pair

Question

Compare two objects if any one of the object not having key pair.

    var itemA= [{"name": "saran", "address":"chennai"},
                       {"name": "elango", "address":"chennai"},
                       {"name": "kala", "address": "chennai"}];

    var itemB= [{"name": "saran", "address":"chennai"},
                       {"name": "elango", "address":"chennai"}]; 

I wrote following code to compare two objects,

  function compareJSON(itemA, itemB) {        
      for(var prop in itemA) {
          if(itemB.hasOwnProperty(prop)) {
              switch(typeof(itemA[prop])) {
                 case "object":
                    compareJSON(itemA[prop], itemB[prop]);
                       break;
                         default:
                             if(itemA[prop] !== itemB[prop]) {
                             }
                         break;
                }
          }
     }

}

Here i have two object i need to compare above two object. I used to for loop for compare two object with hasOwnProperty() method. the prop is having itemA of object it's checked with itemB object if it's different i took itemA object.

Here problem is not able compare itemA 3rd value not able to compare because in itemB does not have a 3rd element.

Answer 1

Check this out.

If not equal, you can write your custom modifications/logic.

 var itemA= [{"name": "saran", "address":"chennai"}, {"name": "elango", "address":"chennai"}, {"name": "kala", "address": "chennai"}]; var itemB= [{"name": "saran", "address":"chennai"}, {"name": "elango", "address":"chennai"}]; let keysA = Object.keys(itemA); let keysB = Object.keys(itemB); if(keysA.length === keysB.length) { let flag = true; keysA.map( a => { if(!keysB.includes(a)) { flag = false; } }) flag ? alert('Equal') : alert('Not equal'); } else { alert('Not equal'); } 

Answer 2

Array.prototype.reduce() , JSON.stringify() and Array.prototype.includes() can be combined to find the differences between Arrays A and B .

 // A. const A = [ {name: "saran", address:"chennai"}, {name: "elango", address:"chennai"}, {name: "kala", address: "chennai"} ] // B. const B = [ {name: "saran", address:"chennai"}, {name: "elango", address:"chennai"} ] // Differences. const differences = A.reduce((differences, object) => (!JSON.stringify(B).includes(JSON.stringify(object)) && [...differences, object] || differences), []) // Log. console.log(differences)