README.md

leaflet-polydiff

Leaflet layer for efficient data fetching.

leaflet-polydiff keeps track of user movements to compute the difference between newly visited area in the map, and the sum of all previously visited area, thanks to Turf.js.

The resulting polygon can be used to make API calls to a backend, in order to optimize data fetching of GeoJSON feature.

Installation

You can install leaflet-polydiff with NPM:

npm i @20tab/leaflet-polydiff

Or with YARN:

yarn add @20tab/leaflet-polydiff

Usage

leaflet-polydiff is distributed as an ES2015 module, and is intended to be used with a module bundler.

import * as L from "leaflet";

import PolyDiff from "@20tab/leaflet-polydiff";

/**
 * Map initialization.
 */
const copy =
    "© <a href='https://www.openstreetmap.org/copyright'>OpenStreetMap</a> contributors";
const url = "https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png";
const osm = L.tileLayer(url, { attribution: copy });

const leafletMap = L.map("map", {
    layers: [osm],
    zoom: 15,
    center: [43.71994, 10.948968],
});

/**
 * PolyDiff activation.
 */

PolyDiff().addTo(leafletMap);

leafletMap.on("polydiff", (event) => {
    // The event object will carry a diff polygon.
    event.diff;
});

Props

Name	Type	Default	Description
eventName?	string	"polydiff"	The event name for the diff event.
pane?	LayerOptions	"overlayPane"	See link.
attribution?	LayerOptions	null	See link.