Function appendHeader

deps/undici/undici.js:11566–11585

(headers, name, value)

    }
    __name(fill, "fill");
    function appendHeader(headers, name, value) {
      value = headerValueNormalize(value);
      if (!isValidHeaderName(name)) {
        throw webidl.errors.invalidArgument({
          prefix: "Headers.append",
          value: name,
          type: "header name"
        });
      } else if (!isValidHeaderValue(value)) {
        throw webidl.errors.invalidArgument({
          prefix: "Headers.append",
          value,
          type: "header value"
        });
      }
      if (getHeadersGuard(headers) === "immutable") {
        throw new TypeError("immutable");
      }
      return getHeadersList(headers).append(name, value, false);
    }
    __name(appendHeader, "appendHeader");
    function headersListSortAndCombine(target) {
      const headersList = getHeadersList(target);