var str : string = "魑魅魍魉";
console.log("str:", str);
console.log("str len:", str.length);
var enc : TextEncoder = new TextEncoder();
var dec : TextDecoder = new TextDecoder();
var buf : Uint8Array = enc.encode(str);
console.log("buf:", buf);
console.log("buf len:", buf.length);
for (var i = 0; i <= buf.length; i++) {
  console.log(`buf[${i}]: ${ dec.decode(buf.slice(0, i)) }`);
}