find charset from string data by the charset mark like "\x0aCharset: "
npm install find-charset
import findCharset from "find-charset";
// or
// const findCharset = require("find-charset").default;
const found = findCharset(fs.readFileSync(`${__dirname}/sjis_lf.txt`), "\x0acharset: ", {
charsetEndMark: "\x0a",
caseInsensitive: true,
});
assert(found === "Shift_JIS");