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    use-supercluster
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    0.4.0 • Public • Published

    useSupercluster

    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 }
    });

    Installation

    You will need to install Supercluster as a peer dependency of this package.

    yarn add supercluster use-supercluster
    

    Examples

    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.

    Mapbox

    Full instructions and an example can be found here.

    Google Maps

    Full instructions and an example can be found here.

    Leaflet

    Full instructions and an example can be found here.

    Configuration

    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.

    Map & Reduce 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>

    Install

    npm i use-supercluster

    DownloadsWeekly Downloads

    29,650

    Version

    0.4.0

    License

    MIT

    Unpacked Size

    17.8 kB

    Total Files

    11

    Last publish

    Collaborators

    • leighhalliday