Basic webp integration (#103)

src/codecs/webp/encoder.ts

@@ -0,0 +1,16 @@
+import EncoderWorker from './Encoder.worker';
+
+export interface EncodeOptions { quality: number; }
+export interface EncoderState { type: typeof type; options: EncodeOptions; }
+
+export const type = 'webp';
+export const label = 'WebP';
+export const mimeType = 'image/webp';
+export const extension = 'webp';
+export const defaultOptions: EncodeOptions = { quality: 7 };
+
+export async function encode(data: ImageData, options: EncodeOptions) {
+  // We need to await this because it's been comlinked.
+  const encoder = await new EncoderWorker();
+  return encoder.encode(data, options);
+}