Check If The Bytes Sequence Is Valid Utf-8 Sequence In Javascript

Is there a simple way to check if string is valid UTF-8 sequence in JavaScript? I really do not want to end with a regular expression like this: Regex to detect invalid UTF-8 strin

Solution 1:

UTF-8 is in fact a simple encoding, but still what you are asking can't be done with a one-liner. You have to:

1. Override the Content-Type of the response to have a byte array in your script and prevent the browser/library to interpret the response itself
2. Looping over the bytes to make characters. Note that UTF-8 is a variable-length encoding, and that's why some sequences are invalid.
3. If an invalid octet is found, skip it
4. If needed, deserialize the JSON/XML/whatever string to a JavaScript object, possibly by handing failures

Deciding if a certain array is a valid UTF-8 sequence is quite a straightforward task (just a bunch of if statements and bit shiftings), but again it's not a one line thing.