Jorik

Posted on Apr 9, 2021

Country Code to Flag Emoji

#javascript #tutorial #webdev

Instead of showing boring country codes like US, CH, NL, it is much nicer to show the flag emojis, 🇺🇸 🇨🇭 and 🇳🇱, right? This isn't hard to do with some JavaScript.

function getFlagEmoji(countryCode) {
  const codePoints = countryCode
    .toUpperCase()
    .split('')
    .map(char =>  127397 + char.charCodeAt());
  return String.fromCodePoint(...codePoints);
}

The flag emoji is a combination of the two unicode region characters, located at unicode position 127462 for the letter A. For CH (Switzerland), we want the indexes to be 127464 and 127469.

Run down of what happens in this little function;

First, uppercase the country code input to ensure we're getting the right character position.
Split into an array, and iterate over each character.
We can receive the UTF-16 code index from the character using charCodeAt. The UTF-16 A is positioned at 65, and we have subtracted this from the region A character index 127462, explaining the hardcoded 127397 value (127462 - 65). To get the correct flag emoji index, we simply add the received index to the offset number.
Finally, the String.fromCodePoint function will return the emoji characters for the computed indexes.

getFlagEmoji('US') = 🇺🇸
getFlagEmoji('NL') = 🇳🇱
getFlagEmoji('CH') = 🇨🇭

Instant flags without additional resources!

Top comments (21)

Jon Randy 🎖️ • Apr 9 '21 • Edited

Nice. I'm gonna save a 1-liner Gist for future use:

const getFlagEmoji = countryCode=>String.fromCodePoint(...[...countryCode.toUpperCase()].map(x=>0x1f1a5+x.charCodeAt()))

Jorik • Apr 9 '21

Nice compact improvement! Although I would also suggest optimising for readability :-)

Jon Randy 🎖️ • Apr 9 '21

I did. This one was too much... :P

const getFlag=c=>String.fromCodePoint(...[...c.toUpperCase()].map(x=>0x1f1a5+x.charCodeAt()))

Jorik • Apr 9 '21 • Edited

You inspired me to optimise the example function in the article to have less redundant code. :-)

An alternative implementation could use the replace method to replace each character.

function getFlagEmoji(countryCode) {
  return countryCode.toUpperCase().replace(/./g, char => 
      String.fromCodePoint(127397 + char.charCodeAt())
  );
}

Jacob Evans • Jan 7 '22

This turned into a CodeWars challenge lol

Peter Repukat • Jan 12 '22

Combined both of them, and I like this best. lol

(c)=>c.replace(/./g,(ch)=>String.fromCodePoint(0x1f1a5+ch.toUpperCase().charCodeAt()))

Andrew Bone • Apr 9 '21 • Edited

One problem with this approach is it leaves you at the mercy of your OS (and even browser).

In this image I'm running the same fiddle on the same OS (windows 10) but in different browsers (the top one is chrome the bottom is firefox).

That all being said it's a nice way to keep things looking right for the OS. And a great way to keep code light.

Ferdinand • Jun 24 '23

Thank you, very nice! I just wanted to share a performance improvement:

function getFlagEmoji(countryCode) {
  return [...countryCode.toUpperCase()].map(char => 
      String.fromCodePoint(127397 + char.charCodeAt())
  ).reduce((a, b) => `${a}${b}`);
}

From the benchmark your original code is 12% slower and the version in the comments using replace is 14% slower: jsperf benchmark

Aj • Nov 26 • Edited

Really inspiring thank you so much, I got really inspired and decided to create a country's capital finder just displaying the capital of any country in python and run on Flask maybe this would help you find any capital you want :)

(dev.to/amedalen/any-countrys-capit...)

Once again thank you for this wonderful post.