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": ["[email protected]", "[email protected]", "[email protected]", "[email protected]"] }

const old = [
  {
    "ccAddresses": ["[email protected]", "[email protected]"],
  },
  { 
    "ccAddresses": ["[email protected]", "[email protected]"],
    "toAddresses": ["[email protected]", "[email protected]"],
  }
];

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

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@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