A hook for using Supercluster with React.
const { clusters, supercluster } = useSupercluster({
points: [],
bounds: [
-1.2411810957931664,
52.61208435908725,
-1.0083656811012531,
52.64495957533833
],
zoom: 12,
options: { radius: 75, maxZoom: 20 }
});
You will need to install Supercluster as a peer dependency of this package.
yarn add supercluster use-supercluster
This package contains an example along with tests, but full examples with instructions in the most popular mapping libraries for React can be found below.
Full instructions and an example can be found here.
Full instructions and an example can be found here.
Full instructions and an example can be found here.
The last (fourth) argument passed to the useSupercluster
hook are options that are passed directly to the instance of Supercluster. You can use any of Supercluster's options.
As an example, you can use map
and reduce
to keep track of a total value summed up from across the points. In this case we have the total cost
, the max severity
, plus another count
(which is redundant because Supercluster gives us the point_count
property).
const options = {
radius: 75,
maxZoom: 20,
map: props => ({
cost: props.cost,
severity: props.severity,
count: 1
}),
reduce: (acc, props) => {
acc.count += 1;
acc.cost += props.cost;
acc.severity = Math.max(acc.severity, props.severity);
return acc;
}
};
I found map
and reduce
a little confusing! The value returned from map
of the first point is used as the initial value passed as the accumulator to the reduce
function. The only props
you have available in reduce
are the ones returned from map
. You technically don't need to return a value from reduce
(it's not used), but instead need to mutate the accumulator object.
Then these accumulated properties can be used and are available on each cluster:
<ul>
{clusters.map(point => {
const properties = point.properties || {};
if (properties.cluster) {
return (
<li key={point.id}>
<h2>Points: {properties.point_count}</h2>
<p>Cost: {properties.cost.toFixed(2)}</p>
<p>Severity: {properties.severity}</p>
<p>Count: {properties.count}</p>
</li>
);
} else {
return <li key={properties.crimeId}>{properties.category}</li>;
}
})}
</ul>