Combine Arrays in JavaScript Without Duplicates

Question

I need to combine ccAddresses and toAddresses values into just one set of array without duplication.

Expected Output

   { "newAddresses": ["john@gmail.com", "joshua@gmail.com", "jane@gmail.com", "james@gmail.com"] }

const old = [
  {
    "ccAddresses": ["john@gmail.com", "joshua@gmail.com"],
  },
  { 
    "ccAddresses": ["jane@gmail.com", "joshua@gmail.com"],
    "toAddresses": ["jane@gmail.com", "james@gmail.com"],
  }
];

const news = old.flatMap((val, index) => ({
"newAddress": val.ccAddresses
}))

console.log(news)

applies only to `ccAddresses`? is expected output an object? — Giorgi Moniava, Sep 09 '22 at 09:50

Mykyta Halchenko · Accepted Answer · 2022-09-09T10:10:55.017

1

const res = Array.from(new Set([...old.flatMap(x => [...x.ccAddresses])]))

UPDATED(as per new author's requirement):

Array.from(new Set([...old.flatMap(x => [...x.ccAddresses].concat([...x.toAddresses || []]))]))

edited Sep 09 '22 at 10:10

answered Sep 09 '22 at 09:55

Mykyta Halchenko

720
1
3
21

@Joseph Array.from(new Set([...old.flatMap(x => [...x.ccAddresses].concat([...x.toAddresses || []]))])) – Mykyta Halchenko Sep 09 '22 at 10:10
1

What about this? `const res = Array.from(new Set([...old.flatMap(x => [...x.ccAddresses, ...x.toAddresses])]))` – Joseph Sep 09 '22 at 10:10
Is that one ok too? – Joseph Sep 09 '22 at 10:12
@Joseph if there is no `toAddresses ` it will be an exception, this is whi I added `[...x.toAddresses || []]` – Mykyta Halchenko Sep 09 '22 at 10:18

Combine Arrays in JavaScript Without Duplicates

1 Answers1