How can I "zoom" into one US state from a topojson of US counties?

Question

I have a D3 topoJSON implementation in React Native that displays US counties' paths and state paths to form a map. I want to essentially "zoom" in or scale up to show only one state with the counties. The bordering paths of the states should be around the focused state. How can I do this?

const COUNTIES = feature(
  counties,
  counties.objects.counties
).features;
const [countyList, setCountyList] = useState([]);

  const mapExtent = useMemo(() => {
    return dimensions.width > dimensions.height / 2
      ? dimensions.height / 2 - 90
      : dimensions.width - 90;
  }, [dimensions]);
  const statePaths = useMemo(() => {
    const projection = d3.geoMercator().fitSize([mapExtent, mapExtent], {
      type: "FeatureCollection",
      features: COUNTIES,
    });
    const geoPath = d3.geoPath().projection(projection);
    const svgPaths = COUNTIES.map(geoPath);
    return svgPaths;
  }, [dimensions]);
  useEffect(() => {
    setCountyList(
      statePaths.map((path, i) => {
        const curCounty = COUNTIES[i].properties.NAME;

        const isCountyNameInData = data.some(
          (county) => county.name === curCounty + " County"
        );

        const curCountyData = isCountyNameInData
          ? data.find((county) => county.name === curCounty + " County")["data"]
          : null;

        return (
          <Path
            key={COUNTIES[i].properties.NAME}
            d={path}
            stroke={"#535252"}
            strokeOpacity={0.3}
            strokeWidth={0.6}
            fill={colorScale(curCountyData)}
          />
        );
      })
    );
  }, [data]);