Function transcode

crates/celld/js/node_buffer.js:734–766

(source, fromEnc, toEnc)

    // '?', like Node's ICU-backed transcode. The 128 MiB cap mirrors
    // Workerd's isolate external-memory limit.
    transcode(source, fromEnc, toEnc) {
      const src = __u8(source);
      if (!src) throw __bufType("source",
        "an instance of Buffer or Uint8Array", source);
      const from = __normEnc(fromEnc);
      const to = __normEnc(toEnc);
      const ok = ["ascii", "latin1", "utf8", "utf16le"];
      if (!from || !ok.includes(from)) throw __badEnc(fromEnc);
      if (!to || !ok.includes(to)) throw __badEnc(toEnc);
      if (src.length >= 134217728)
        throw new RangeError("Cannot transcode a buffer this large");
      if (from === "utf16le" && src.length % 2 !== 0)
        throw __bufErr(RangeError, "ERR_INVALID_ARG_VALUE",
          "Unable to transcode buffer");
      let s;
      if (from === "utf8" && to === "utf16le") {
        try {
          s = new TextDecoder("utf-8", { fatal: true }).decode(src);
        } catch {
          throw new TypeError("Unable to transcode buffer");
        }
      } else if (from === "utf8") {
        s = new TextDecoder().decode(src); // replacement characters
      } else {
        s = __decodeStr(src, from);
      }
      if (to === "ascii" || to === "latin1") {
        const max = to === "ascii" ? 0x7f : 0xff;
        s = Array.from(s,
          (c) => c.charCodeAt(0) > max ? "?" : c).join("");
      }
      return new NodeBuffer(__encodeStr(s, to));
    },
    Blob: globalThis.Blob,
    File: globalThis.File,
    atob: globalThis.atob,