proc addFormDataModule(ctx: JSContext): Opt[void] {....raises: [], tags: [],
    forbids: [].}

proc append(ctx: JSContext; this: FormData; name: string; val: JSValueConst;
            rest: varargs[JSValueConst]): Opt[void] {....raises: [], tags: [],
    forbids: [].}

proc constructEntryList(form: HTMLFormElement; submitter: Element = nil;
                        encoding = "UTF-8"): seq[FormDataEntry] {....raises: [],
    tags: [RootEffect], forbids: [].}

proc newFormData0(urandom: PosixStream): FormData {....raises: [], tags: [],
    forbids: [].}

proc toNameValuePairs(list: seq[FormDataEntry]): seq[tuple[name, value: string]] {.
    ...raises: [], tags: [], forbids: [].}