What is quickest and easiest way to merge two arrays without duplicates in Angular2/Typescript (ES6).
p.s. Arrays contain nested objects.
I know there are lot of answers already there. That's why I'm confused. I tried answers on this, but I couldn't get it working.
Thanks in advance.
That's not related to angular2/typescript, my answer works with ES6.
Use uniq function from lodash (https://lodash.com/docs/4.17.4#uniq) on items from your sources array like this:
const arrA = [1, 2, 3, 4];
const arrB = [3, 4, 5, 6];
const arr = _.uniq([...arrA, ...arrB])
// [1, 2, 3, 4, 5, 6]
And for nested object, use uniqBy (https://lodash.com/docs/4.17.4#uniqBy) or uniqWith.
const arrA = [{id: 1, n: 'e'}, {id: 2, n: 'z'}];
const arrB = [{id: 2, n: 'z'}, {id: 3, n: 'c'}];
const arr = _.uniqBy([...arrA, ...arrB], 'id')
// [{id: 1, n: 'e'}, {id: 2, n: 'z'}, {id: 3, n: 'c'}]
But you need a unique identifier (id here) to know when duplicates.
[EDIT] In case, you don't have a unique identifier and want to use whole objects to deduplicate, you can do it like this:
const arrA = [{a: 'a'}, {b: 'b'}];
const arrB = [{b: 'b'}, {c: 'c'}];
const arr = _.uniqBy([...arrA, ...arrB], JSON.stringify)
// [{a: 'a'}, {b: 'b'}, {c: 'c'}]
It will stringify all your object to check if same string values, so remember it could be costly on huge objects/array. That's a better practise to have a unique identifier.
If you use typescript, you can go like this:
const a = [1, 2, 3];
const b = [2, 3, 4, 5];
result = a.concat(b.filter(x => a.every(y => y !== x))); //[1, 2, 3, 4, 5];
With b.filter(x => a.every(y => y !== x)) you are filtering out the duplicates.
If you need this for multiple arrays to be concatenated, you'll need to make a function where you will loop the arrays but again with the same approach as above.
function mergeArraysWithoutDuplicates(arrays: any[]){
var result = [];
for(const array in arrays){
result = result.concat(array.filter(x => result.every(y => y !== x));
}
return result;
}
The code is not tested, but should be something like this, depends on the needs. As a result the function will return new array without duplicates.
