V8 only supports Latin-1/ISO-8859-1 and UTF16 as the underlying representation of a string. If the content uses Latin-1/ISO-8859-1 as the underlying representation, this function will return true; otherwise, it returns false.
If this method returns false, that does not mean that the string contains some characters not in Latin-1/ISO-8859-1. Sometimes a Latin-1 string may also be represented as UTF16.
const { isStringOneByteRepresentation } = require('node:v8');
const Encoding = {
latin1: 1,
utf16le: 2,
};
const buffer = Buffer.alloc(100);
function writeString(input) {
if (isStringOneByteRepresentation(input)) {
buffer.writeUint8(Encoding.latin1);
buffer.writeUint32LE(input.length, 1);
buffer.write(input, 5, 'latin1');
} else {
buffer.writeUint8(Encoding.utf16le);
buffer.writeUint32LE(input.length * 2, 1);
buffer.write(input, 5, 'utf16le');
}
}
writeString('hello');
writeString('你好');