How to get the difference between two arrays of objects in JavaScript

For those who like one-liner solutions in ES6, something like this:

const arrayOne = [ 
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer" },
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed" },
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi" },
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal" },
  { value: "a63a6f77-c637-454e-abf2-dfb9b543af6c", display: "Ryan" },
];
          
const arrayTwo = [
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer"},
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed"},
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi"},
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal"},
];

const results = arrayOne.filter(({ value: id1 }) => !arrayTwo.some(({ value: id2 }) => id2 === id1));

console.log(results);

You could use Array.prototype.filter() in combination with Array.prototype.some().

Here is an example (assuming your arrays are stored in the variables result1 and result2):

//Find values that are in result1 but not in result2
var uniqueResultOne = result1.filter(function(obj) {
    return !result2.some(function(obj2) {
        return obj.value == obj2.value;
    });
});

//Find values that are in result2 but not in result1
var uniqueResultTwo = result2.filter(function(obj) {
    return !result1.some(function(obj2) {
        return obj.value == obj2.value;
    });
});

//Combine the two arrays of unique entries
var result = uniqueResultOne.concat(uniqueResultTwo);

Using only native JS, something like this will work:

const a = [{ value:"0", display:"Jamsheer" }, { value:"1", display:"Muhammed" }, { value:"2", display:"Ravi" }, { value:"3", display:"Ajmal" }, { value:"4", display:"Ryan" }];
const b = [{ value:"0", display:"Jamsheer", $$hashKey:"008" }, { value:"1", display:"Muhammed", $$hashKey:"009" }, { value:"2", display:"Ravi", $$hashKey:"00A" }, { value:"3", display:"Ajmal", $$hashKey:"00B" }];

// A comparer used to determine if two entries are equal.
const isSameUser = (a, b) => a.value === b.value && a.display === b.display;

// Get items that only occur in the left array,
// using the compareFunction to determine equality.
const onlyInLeft = (left, right, compareFunction) => 
  left.filter(leftValue =>
    !right.some(rightValue => 
      compareFunction(leftValue, rightValue)));

const onlyInA = onlyInLeft(a, b, isSameUser);
const onlyInB = onlyInLeft(b, a, isSameUser);

const result = [...onlyInA, ...onlyInB];

console.log(result);

Tags:

Javascript

Arrays

Object

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