facebook/lexical · error

Unrecognized charset

Error message

Unrecognized charset

What it means

LexicalCharacterLimitPlugin computes the current text length using a charset-dependent strlen function. Only 'UTF-8' (byte-length counting via utf8Length) and 'UTF-16' (JS string length) are supported; passing any other charset value makes the memoized strlen throw 'Unrecognized charset'.

Source

Thrown at packages/lexical-react/src/LexicalCharacterLimitPlugin.tsx:91

    remainingCharacters,
  }: {
    remainingCharacters: number;
  }) => JSX.Element;
}): JSX.Element {
  const [editor] = useLexicalComposerContext();

  const [remainingCharacters, setRemainingCharacters] = useState(maxLength);

  const characterLimitProps = useMemo(
    () => ({
      remainingCharacters: setRemainingCharacters,
      strlen: (text: string) => {
        if (charset === 'UTF-8') {
          return utf8Length(text);
        } else if (charset === 'UTF-16') {
          return text.length;
        } else {
          throw new Error('Unrecognized charset');
        }
      },
    }),
    [charset],
  );

  useCharacterLimit(editor, maxLength, characterLimitProps);

  return renderer({remainingCharacters});
}

View on GitHub (pinned to 76a22dcba9)

Solutions

1. Pass charset='UTF-8' or charset='UTF-16' exactly (case-sensitive, with hyphen).
2. Normalize any external config value to one of the two supported strings before rendering.
3. If you need another encoding, supply the counting logic yourself or omit the plugin and compute limits manually.
4. Check the plugin's prop types (charset?: 'UTF-8' | 'UTF-16') to catch invalid values at compile time.

Example fix

// before
<CharacterLimitPlugin charset="utf-8" maxLength={280} />
// after
<CharacterLimitPlugin charset="UTF-8" maxLength={280} />

const SUPPORTED = new Set(['UTF-8', 'UTF-16']);
if (!SUPPORTED.has(charset)) {
  throw new Error(`charset must be 'UTF-8' or 'UTF-16', got ${charset}`);
}

function isSupportedCharset(c: unknown): c is 'UTF-8' | 'UTF-16' {
  return c === 'UTF-8' || c === 'UTF-16';
}

let strlen: (text: string) => number;
try {
  strlen = computeStrlen(charset);
} catch (e) {
  if (e instanceof Error && e.message === 'Unrecognized charset') {
    strlen = (t) => t.length; // fallback to UTF-16 semantics
  } else { throw e; }
}

When it happens

Trigger: Rendering <CharacterLimitPlugin charset="..." /> with a charset value other than the string 'UTF-8' or 'UTF-16' — e.g. 'utf-8' (lowercase), 'ASCII', undefined, or a typo like 'UTF8'.

Common situations: Passing lowercase 'utf-8' from a config value; assuming 'UTF8' (no hyphen) is valid; feeding charset from an enum defined elsewhere with unsupported values; leaving charset undefined expecting a default.

Related errors

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• CodeHighlightPlugin: CodeNode or CodeHighlightNode not regis
• CodeHighlightPlugin: CodeNode or CodeHighlightNode not regis

AI-assisted analysis of facebook/lexical@76a22dcba9 (2026-08-31). Data as JSON: /api/errors/b89c3e5b73fcf421. Report an issue: GitHub.