leaflet.dexie
Leaflet.dexie.js
A Leaflet plugin for offline maps storage using library Dexie.js.
The source code is based on leaflet.offline with the following differences:
- instead of idb, we use dexie.js which is efficient, stable and well supported indexedDB library.
- instead of having all maps in a single table(store), each map is saved in its own table and can add other user-defined attributes like size, center, bounds, etc.
Dependencies
- leaflet.js - for map controls
- dexie.js - to store tiles in indexedDB asynchronously
Demo
The Demo implements creation and deletion of offline maps and can simulate offline map display.
Usage
Main usage is for offline maps, but could be also used to store other information. API documentation is available.
Manual installation
Add a <script> tag to your HTML page after leaflet and dexie. You can web-load the script, or download file leaflet.dexie.min.js and load it locally. See code below.
Minimal code sample
<!doctype html>
<html>
<head>
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.7.1/dist/leaflet.css" />
<script src="https://unpkg.com/leaflet@1.7.1/dist/leaflet.js"></script>
<script src="https://unpkg.com/dexie@latest/dist/dexie.js"></script>
<script src="https://cdn.jsdelivr.net/gh/helgasoft/leaflet.dexie/dist/leaflet.dexie.min.js"></script>
<!-- or local copy:
<script src="js/leaflet.dexie.min.js"></script> -->
</head>
<body>
<div id="map" style="height: 75vh"></div>
<p>
<input type='button' value='Save map' onclick='savem()' />
<input type='button' value='Delete map' onclick='delm()' />
</p>
press F12 to watch IndexedDB/leaflet-maps in tab <i>Application</i>(Chrome), <i>Storage</i>(FF) or <i>Debugger</i>(Edge)
<script>
let map = L.map('map');
map.setView(L.latLng(47.2572, 3.6842), 18);
let baseLayer = L.tileLayer.offline('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', { subdomains: 'abc', maxZoom: 18});
baseLayer.addTo(map);
let control = L.control.savetiles(baseLayer, {
'confirmSave': function(status, saveCallback) {
var newTname = prompt("Please enter map name ("+status._tilesforSave.length+" tiles):", "");
if (newTname == null || newTname == "") return; // user cancelled the prompt
saveCallback(newTname);
}
});
control.addTo(map);
control.openDB();
savem = function() {
control.setBounds(map.getBounds());
control.saveMap();
}
delm = function() {
control.deleteTable(control.dtable.name);
}
baseLayer.on('loadend', function(e) { // all tiles just saved
control.putItem('mapSize', e.mapSize);
control.getItem('mapSize').then( (msize) => {
alert("size of map '"+ control.dtable.name +"' is "+ msize +' bytes');
});
});
</script>
</body>
</html>
IndexedDB
indexedDB is the standard database in the browser. Press F12 to open inspection sidebar, hit tab Application(Chrome), Storage(FF) or Debugger(Edge) and watch IndexedDB. The database name is leaflet-maps. Watch also tab Console for errors.
