The large majority of users of TextEncoder and TextDecoder do not make use of streaming capabilities. Instead they just need to decode a single chunk, or encode a single chunk. We should consider adding a static utility method to TextEncoder / TextDecoder to cater to this use case.

// current
const data = new TextDecoder().decode(new Uint8Array(/** data here */));

// proposed
const data = TextDecoder.decode(new Uint8Array(/** data here */));

I propose the following API be added:

dictionary TextDecoderOptionsWithLabel : TextDecoderOptions {
  DOMString label = "utf-8";
};

interface TextDecoder {
  static USVString decode(optional [AllowShared] BufferSource input, optional TextDecoderOptionsWithLabel options = {});
}

interface TextEncoder {
  static Uint8Array encode(optional USVString input = "");
  static TextEncoderEncodeIntoResult encodeInto(USVString source, [AllowShared] Uint8Array destination);
}

The exact name of the method should be something different though - the static method and prototype method would name clash in this example which is confusing.

Internally this would behave exactly like a single use non streaming encoder.