![]() ![]() For example, the dog emoji □ has the code point U+1F436. Unicode code points and character encodingĮach character in the Unicode standard is assigned an identification number, or code point. Why use both? Western languages typically are most efficiently encoded with UTF-8 (since most characters would be represented with 1 byte only), while Asian languages can usually produce smaller files when using UTF-16 as encoding. On the other hand, UTF-16 uses between 2 and 4 bytes. It’s a superset of ASCII, so the first 128 characters are identical to those in the ASCII table. ![]() UTF-8 uses between 1 and 4 bytes to represent all characters. The most common ones are UTF-8 and UTF-16 on the web, UTF-8 is significantly more popular. Unicode can be implemented in multiple character encoding standards. Unicode 12.0 was released just a few days ago, and includes over 137,000 characters. The solution was to adopt a standard called Unicode, aiming to include every single character of every modern and historic script, plus a variety of symbols. The problem is that 128 characters might be enough to represent all the characters English-speakers normally use, but it’s orders of magnitude too small to represent every character of every script worldwide, including emojis. In the ASCII standard, for example, the letter M (uppercase m) is encoded as number 77 (4D in hex). It also included a bunch of “non-printable” characters, such as newline, tab, carriage return, etc. It used 7 bit and could represent a total of 128 characters, including the Latin alphabet (both uppercase and lowercase), digits and basic punctuation symbols. The first of such conventions, or character encodings, was ASCII (American Standard Code for Information Interchange). In order to be able to represent text, we are mapping each character to a specific number, and have conventions for how display them. How we got to emojis: a brief explanation of character encodingĬomputers work with bytes, which are just numbers. If you’re dealing with Unicode strings in your application, you need to take into account that characters could be represented in multiple ways. In the first “Zoë”, the ë character (e with umlaut) was represented a single Unicode code point, while in the second case it was in the decomposed form. In fact, while the two strings above look identical on screen, the way they’re represented on disk, the bytes saved in the file, are different. In certain situations, I would see the same person added twice because the names wouldn’t compare as equal strings. It first hit me many years ago, when I was building an app (in Objective-C) that imported a list of people from a user’s address book and social media graph, and filtered out duplicates. This is not another one of JavaScript’s oddities, and I could have shown you the very same result with code in almost every other programming language, including Python, Go, and even shell scripts. ![]()
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