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

Question

I have two result sets like this:

// Result 1
[
    { value: \"0\", display: \"Jamsheer\" },
    { value: \"1\", display: \"Muhammed\" },
    { value: \"2\",         


        

Answer 1

You can create an object with keys as the unique value corresponding for each object in array and then filter each array based on existence of the key in other's object. It reduces the complexity of the operation.

ES6

let a = [{ value:"4a55eff3-1e0d-4a81-9105-3ffffd7521d642", 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"}];
let b = [{ value:"4a55eff3-1e0d-4a81-9105-3ffffd7521d642", display:"Jamsheer", $$hashKey:"008"}, { value:"644838b3-604d-4899-8b78-09e4799f586f", display:"Muhammed", $$hashKey:"009"}, { value:"b6ee537a-375c-45bd-b9d4-4dd84a75041d", display:"Ravi", $$hashKey:"00A"}, { value:"e97339e1-939d-47ab-974c-1b68c9cfb536", display:"Ajmal", $$hashKey:"00B"}];

let valuesA = a.reduce((a,{value}) => Object.assign(a, {[value]:value}), {});
let valuesB = b.reduce((a,{value}) => Object.assign(a, {[value]:value}), {});
let result = [...a.filter(({value}) => !valuesB[value]), ...b.filter(({value}) => !valuesA[value])];
console.log(result);

ES5

var a = [{ value:"4a55eff3-1e0d-4a81-9105-3ffffd7521d642", 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"}];
var b = [{ value:"4a55eff3-1e0d-4a81-9105-3ffffd7521d642", display:"Jamsheer", $$hashKey:"008"}, { value:"644838b3-604d-4899-8b78-09e4799f586f", display:"Muhammed", $$hashKey:"009"}, { value:"b6ee537a-375c-45bd-b9d4-4dd84a75041d", display:"Ravi", $$hashKey:"00A"}, { value:"e97339e1-939d-47ab-974c-1b68c9cfb536", display:"Ajmal", $$hashKey:"00B"}];

var valuesA = a.reduce(function(a,c){a[c.value] = c.value; return a; }, {});
var valuesB = b.reduce(function(a,c){a[c.value] = c.value; return a; }, {});
var result = a.filter(function(c){ return !valuesB[c.value]}).concat(b.filter(function(c){ return !valuesA[c.value]}));
console.log(result);