A few days ago, I had to implement a new feature on Puppeteer-Sharp. The library needed to be able to send emojis through its typing simulation. Trying to send and read an 👹 from a WebSocket might be quite confusing. You could get an □ on the other side or an �� on your side, and you would think that’s an encoding issue. Maybe it’s not. Let’s see what the deal is with emojis.

If you know nothing about programming, I bet you would at least feel that emojis are a different kind of character.
If you know something about programming, you know that emojis are not ASCII characters, they are a different thing.
If you’ve coded something related with characters, you might know that they’re related to Unicode.

Let’s declare a variable called emojis

var emojis = "👹 in 🇯🇵";
Console.WriteLine(emojis);

note: The flag might break your IDE. Don’t try this at home.

👹 in 🇯🇵

Cool. It works. Now let’s try to “spell” that string using ToCharArray.

foreach(var c in emojis)
{
    Console.WriteLine(c);
}

Note: This is getting fun. This code broke dotnetfiddle.com. Switching to VS Code.

We get this beautiful result:

�
�

i
n

�
�
�
�

What is a char?

This definition of a char at docs.microsoft.com:

The .NET Framework uses the Char structure to represent a Unicode character. The Unicode Standard identifies each Unicode character with a unique 21-bit scalar number called a code point and defines the UTF-16 encoding form that specifies how a code point is encoded into a sequence of one or more 16-bit values. Each 16-bit value ranges from hexadecimal 0x0000 through 0xFFFF and is stored in a Char structure. The value of a Char object is its 16-bit numeric (ordinal) value.

Two important things here: Chars are Unicode, and chars are 16-bit (2 bytes) objects.

What is an 👹

Most emojis are 32-bit characters so they won’t fit on a 16-bit char. So when we make a ToCharArray of \u1F479 (the ogre) we get a \u1F47 and a 9 .

What is Japan?

Flags are even more interesting because they are emoji sequence. In the case of the Japanese flag, it’s the sequence of the Regional Indicator Symbol Letter J “🇯” and the Regional Indicator Symbol Letter P “🇵”. This makes the Japanese flag a 64-bit character.

Now we can understand why we were getting the following:

�
�

i
n

�
�
�
�

If we use ToCharArray for emojis, we are “breaking” them.

StringInfo to the rescue

According to its documentation:

StringInfo provides functionality to split a string into text elements and to iterate through those text elements.

StringInfo provides a method called GetTextElementEnumerator which helps us split a string not in chars, but into text elements.

So now, if we do this:

var textParts = StringInfo.GetTextElementEnumerator(emojis);
while (textParts.MoveNext())
{
    Console.WriteLine(textParts.Current);
}

We get:

👹

i
n

🇯
🇵

GetTextElementEnumerator splits the Japanese flag into its two emoji characters, but it won’t break it. If you type a 🇯 and then a 🇵, you’ll get a 🇯🇵.

Try it by yourself copying and pasting those characters in this input element.

Don’t stop coding!