feat: Add typings (#6)

Signed-off-by: Richie Bendall <richiebendall@gmail.com>

blob.d.ts

@@ -0,0 +1,18 @@
+/// <reference lib="dom"/>
+
+// /** A file-like object of immutable, raw data. Blobs represent data that isn't necessarily in a JavaScript-native format. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system. */
+declare interface FetchBlob extends Blob {
+    stream(): ReadableStream
+    text(): Promise<string>
+    arrayBuffer(): Promise<ArrayBuffer>
+    toString(): "[object Blob]"
+    [Symbol.toStringTag]: "Blob"
+
+}
+
+declare const FetchBlob: {
+    prototype: FetchBlob
+    new(blobParts?: BlobPart[], options?: BlobPropertyBag): FetchBlob
+};
+
+export = FetchBlob;