function readableAddChunk()

in src/js/node/stream.ts [2809:2864]
56 lines of code
31 McCabe index (conditional complexity)

    function readableAddChunk(stream, chunk, encoding, addToFront) {
      $debug("readableAddChunk", chunk, stream.__id);
      const state = stream._readableState;
      let err;
      if (!state.objectMode) {
        if (typeof chunk === "string") {
          encoding = encoding || state.defaultEncoding;
          if (state.encoding !== encoding) {
            if (addToFront && state.encoding) {
              chunk = Buffer.from(chunk, encoding).toString(state.encoding);
            } else {
              chunk = Buffer.from(chunk, encoding);
              encoding = "";
            }
          }
        } else if (chunk instanceof Buffer) {
          encoding = "";
        } else if (Stream._isUint8Array(chunk)) {
          if (addToFront || !state.decoder) {
            chunk = Stream._uint8ArrayToBuffer(chunk);
          }
          encoding = "";
        } else if (chunk != null) {
          err = new ERR_INVALID_ARG_TYPE("chunk", ["string", "Buffer", "Uint8Array"], chunk);
        }
      }
      if (err) {
        errorOrDestroy(stream, err);
      } else if (chunk === null) {
        state.reading = false;
        onEofChunk(stream, state);
      } else if (state.objectMode || (chunk && chunk.length > 0)) {
        if (addToFront) {
          if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());
          else if (state.destroyed || state.errored) return false;
          else addChunk(stream, state, chunk, true);
        } else if (state.ended) {
          errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
        } else if (state.destroyed || state.errored) {
          return false;
        } else {
          state.reading = false;
          if (state.decoder && !encoding) {
            chunk = state.decoder.write(chunk);
            if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);
            else maybeReadMore(stream, state);
          } else {
            addChunk(stream, state, chunk, false);
          }
        }
      } else if (!addToFront) {
        state.reading = false;
        maybeReadMore(stream, state);
      }
      return !state.ended && (state.length < state.highWaterMark || state.length === 0);
    }