Method append

packages/deno/lib.deno.d.ts:9424–9424

(name: string, value: string | Blob, fileName?: string)

 */
interface FormData extends DomIterable<string, FormDataEntryValue> {
  append(name: string, value: string | Blob, fileName?: string): void;
  delete(name: string): void;
  get(name: string): FormDataEntryValue | null;
  getAll(name: string): FormDataEntryValue[];