function con(n) {
return 0x80 | (n & 0x3f);
}
export function encode(str) {
const arr = str.split("").map(x => x.charCodeAt(0));
return _encode(arr);
}
function _encode(arr) {
if (arr.length === 0) {
return [];
}
const [n, ...ns] = arr;
if (n < 0) {
throw new Error("utf8");
}
if (n < 0x80) {
return [n, ..._encode(ns)];
}
if (n < 0x800) {
return [0xc0 | (n >>> 6), con(n), ..._encode(ns)];
}
if (n < 0x10000) {
return [0xe0 | (n >>> 12), con(n >>> 6), con(n), ..._encode(ns)];
}
if (n < 0x110000) {
return [
0xf0 | (n >>> 18),
con(n >>> 12),
con(n >>> 6),
con(n),
..._encode(ns)
];
}
throw new Error("utf8");
}