Best practices for combining a high pass and low pass filter on an input signal?

I'm using the JavaScript Web audio API. There is a BiquadFilterNode audio node type with which one can use to apply high pass, low pass, bandpass, etc. filters.

I've tried a node graph which looks like:

source->lowpass->highpass->destination

But that turned out to be not what I expected.

Now I am doing:

Source->splitterNode->lowpass,highpass->mergerNode->destination

The result is almost there; it appears that one of these filters is being applied

I've tried everything and I'm not sure what to do to apply both high pass and low pass to an input signal.

Worst case scenario, I just have to make a bandpass, but that is a lot of code to rewrite.

Any help is appreciated, thanks