Function isMentionMode

apps/web/ui/MessageForm/index.tsx:73–101

(message: string, position: number)

}

function isMentionMode(message: string, position: number) {
  const current = message[position - 1];
  const previous = message[position - 2];
  if (
    isMentionCharacter(current) &&
    (isWhitespace(previous) || isUndefined(previous))
  ) {
    return true;
  }

  if (isUsernameCharacter(current)) {
    let index = 2;
    let character = message[position - index];
    while (isUsernameCharacter(character)) {
      index++;
      character = message[position - index];
    }
    const current = character;
    index++;
    const previous = message[position - index];
    if (
      isMentionCharacter(current) &&
      (isWhitespace(previous) || isUndefined(previous))
    ) {
      return true;
    }
  }
  return false;
}

function getMode(message: string, position: number) {
  return isMentionMode(message, position) ? Mode.Mention : Mode.Standard;