How can I get an output like [item: 'value1', item:'value2', …] in an array of objects in Javascript?

I’m trying to convert a JSON (a list of countries/cities in the world) to an array, and what I’m trying to do with the array is:

1. Leave only the name of the countries
2. Since many of the countries are repeated, only leave them once

I was able to achieve this thanks to this function (just to clarify: in the final project, fetchData is imported from another file and the variable declaration and the array are in a document.addEventListener("DOMContentLoaded", async () => {}, this is just one for testing purposes)

async function fetchData(url) {
  const response = await fetch(url);
  return await response.json();
}

(async () => {
  let worldCities = await fetchData(
    "https://pkgstore.datahub.io/core/world-cities/world-cities_json/data/5b3dd46ad10990bca47b04b4739a02ba/world-cities_json.json"
  );

  const countries = [...new Set(worldCities.map((item) => item.country))];

  console.log(countries);
})();

.as-console-wrapper { max-height: 100% !important; top: 0; }

With fetchData I asynchronously request a resource (the URL of the .json file), then I map an array with the file and "filter" it as I mentioned above

But the problem is that it works, but not as needed, because the output should be like this

and my output is just an array of country names

I know that I’m mapping (only) the current value required with worldCities.map((item) => item.country) and removing repeated values with [...new Set()]

But how could I make the array returns an object like key/value pairs [country: 'country1', country: 'country2', ...] (or something similar to the output of the image) instead of the normal array ['country1', 'country2', ...]?

Any help is welcome, thank you very much!

>Solution :

map() it again:

const countries = [...new Set(worldCities.map((item) => item.country))].map(country => ({ country }))

Working solution:

async function fetchData(url) {
  const response = await fetch(url);
  return await response.json();
}

(async () => {
  let worldCities = await fetchData(
    "https://pkgstore.datahub.io/core/world-cities/world-cities_json/data/5b3dd46ad10990bca47b04b4739a02ba/world-cities_json.json"
  );

  const countries = [...new Set(worldCities.map((item) => item.country))].map(country => ({ country }))

  console.log(countries);
})();

.as-console-wrapper { max-height: 100% !important; top: 0; }