Compare Two JavaScript Arrays and Remove Duplicates

Compare two Javascript Arrays and remove Duplicates

array1 = array1.filter(function(val) {
  return array2.indexOf(val) == -1;
});

Or, with the availability of ES6:

array1 = array1.filter(val => !array2.includes(val));

filter() reference here

indexOf() reference here

includes() reference here

Compare 2 Arrays of Objects and Remove Duplicates

One option with O(N) complexity would be to make a Set of the ids in cars1, then spread cars1 and a filtered cars2 into the ouput array, with the filter testing whether the id in the car being iterated over in cars2 is included in the Set:

var cars1 = [    {id: 2, make: "Honda", model: "Civic", year: 2001},    {id: 1, make: "Ford",  model: "F150",  year: 2002},    {id: 3, make: "Chevy", model: "Tahoe", year: 2003},];
var cars2 = [    {id: 3, make: "Kia",    model: "Optima",  year: 2001},    {id: 4, make: "Nissan", model: "Sentra",  year: 1982},    {id: 2, make: "Toyota", model: "Corolla", year: 1980},];const cars1IDs = new Set(cars1.map(({ id }) => id));const combined = [  ...cars1,  ...cars2.filter(({ id }) => !cars1IDs.has(id))];console.log(combined);

Compare two javascript arrays and remove duplicate entries

Realistically you want to do something like:

[a, b, c] - [a, b] 

Which would give you c. You can achieve this using .some, which allows you to "customize" the includes functionality.

See example below:

const arr1 = [  {"member_name":"Test1","item":"Sword"},  {"member_name":"Test2","item":"Sword"}];
const arr2 = [  {"member_name":"Test1","item":"Sword"},  {"member_name":"Test2","item":"Sword"},  {"member_name":"Test1","item":"Shield"}];
const res = arr2.filter(({member_name:a, item:x}) => !arr1.some(({member_name:b, item:y}) => a === b && x === y));console.log(res);

How to compare two arrays and remove duplicate objects by complete iteration

You could use a Set for the given id and filter selectedRows with the set.

var deSelectedRows = [{ PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC01"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC02"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC03"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC04"}],    selectedRows = [{ PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC01"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC02"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC03"}, { PoHeaderKey: 129, OrderNo: "WS1", LineNo: 1, id: "BRIC04"}],    ids = new Set(deSelectedRows.map(({ id }) => id));
selectedRows = selectedRows.filter(({ id }) => !ids.has(id));
console.log(selectedRows);

JS compare two arrays with objects and remove duplicated by property name ES6 way

Array.includes won't work because in javascript {} !== {}. You'll need another way like Array.every to check that every object in the other array doesn't have the same value of the property item as the current object. Also, you need to do both arr1.filter(...) and arr2.filter(...) and concat the results:

arr3 = [].concat(
    arr1.filter(obj1 => arr2.every(obj2 => obj1.item !== obj2.item)),
    arr2.filter(obj2 => arr1.every(obj1 => obj2.item !== obj1.item))
);

Example:

let arr1 = [{  item:"apple",  description: "lorem"},{  item:"peach",  description: "impsum"}];
let arr2 = [{  item:"apple", description: "dolor"},{  item:"grape", description: "enum"}];
let arr3 = [].concat(    arr1.filter(obj1 => arr2.every(obj2 => obj1.item !== obj2.item)),    arr2.filter(obj2 => arr1.every(obj1 => obj2.item !== obj1.item)));
console.log(arr3);

Compare two objects in an array, delete the duplicate data, and combine the different data?

You could collect all with an object with combined keys.

const
    array = [{ id: 1, name: 'test', condition: 'left' }, { id: 2, name: 'example', condition: 'left' }, { id: 1, name: 'test', condition: 'right' }, { id: 3, name: 'foobar', condition: 'right' }],
    keys = ['id', 'name'],
    result = Object.values(array.reduce((r, o) => {
        const key = keys.map(k => o[k]).join('|');
        if (r[key]) r[key].condition = [].concat(r[key].condition, o.condition);
        else r[key] = { ...o };
        return r;
    }, {}));

console.log(result);

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Compare two array and remove if same value using javascript

Here is one more using reduce

var arr1 = [1, 2, 3, 4, 5];var arr2 = [1, 3, 5, 7, 9];

var result = arr1.reduce(function (prev, value) {
    var isDuplicate = false;    for (var i = 0; i < arr2.length; i++) {        if (value == arr2[i]) {            isDuplicate = true;            break;        }    }        if (!isDuplicate) {        prev.push(value);    }        return prev;    }, []);

alert(JSON.stringify(result.concat(arr2)));

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