fetchStream.js

const fetchStream = async (request)=>{
      const controller = new AbortController();
      try {
        const option = {
          method:request.method,
          mode:request.mode,
          credentials: 'include',
          signal:controller.signal
        };
        if(request.headers) option.headers = request.headers;
        if(request.body){
          let chunkSize = 1024;
          const body = new ReadableStream({
            start(controller){
              let i = 0, j = request.body.length;
              const f = _=>{
                if(controller.desiredSize <= 0){
                  chunkSize /= 2;
                  requestAnimationFrame(f);
                  return;
                }
                const start = i;
                const end = i + chunkSize;
                controller.enqueue(request.body.subarray(start, end <= j ? end : j));
                request.onProgress?.(i, j);
                if(end <= j){
                  i = end;
                  if(chunkSize < 1024 * 1024) chunkSize *= 2;
                  requestAnimationFrame(f);
                }else{
                  controller.close();
                }
              }
              f();
            }
          });
          option.body = request.body;
        }

        const response = await fetch(request.url, option);
        const reader = response.body.getReader();
        let result = [];
        let {done, value} = await reader.read();
        const listener = request.type === 'CHUNK_TEXT' ? request.onText : request.onBlob;
        while(!done){
          const v = request.type === 'CHUNK_TEXT' ? Kore.decoder.decode(value) : value;
          result.push(v);
          if(!listener(v)){
            controller.abort();
            return;
          }
          ({done, value} = await reader.read());
        }
        request.onComplete?.(result);
        return result;
      }catch(e){
        if(e.name !== "AbortError") request.onError?.(e.message);
      }
    }