Lazy Source

This example uses OpenLayers v4.0.1. The latest is v.

#### Lazy Source

Example of setting a layer source after construction.

Typically, the source for a layer is provided to the layer constructor. If you need to set a layer source after construction, this can be done with the `layer.setSource()` method.

The layer in the map above is constructed with no source. Use the links below to set/unset the layer source. A layer is not rendered until its source is set.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.layer.Tile
,
- ol.source.OSM

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Lazy Source Example of setting a layer source after construction. var source = new ol.source.OSM(); var layer = new ol.layer.Tile(); var map = new ol.Map({ layers: [layer], target: 'map', view: new ol.View({ center: [0, 0], zoom: 2 }) }); document.getElementById('set-source').onclick = function() { layer.setSource(source); }; document.getElementById('unset-source').onclick = function() { layer.setSource(null); }; button.code { font-family: Monaco,Menlo,Consolas,"Courier New",monospace; font-size: 12px; padding: 5px; margin: 0 5px; } <div id="map" class="map"></div> <button id="set-source" class="code">layer.setSource(source)</button> <button id="unset-source" class="code">layer.setSource(null)</button>

    <!DOCTYPE html>
    <html>
      <head>
        <title>Lazy Source</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
        <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
        <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
        <script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
        <style>
           button.code {
             font-family: Monaco,Menlo,Consolas,"Courier New",monospace;
             font-size: 12px;
             padding: 5px;
             margin: 0 5px;
           }    </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <button id="set-source" class="code">layer.setSource(source)</button>
        <button id="unset-source" class="code">layer.setSource(null)</button>
        <script>
          var source = new ol.source.OSM();

          var layer = new ol.layer.Tile();

          var map = new ol.Map({
            layers: [layer],
            target: 'map',
            view: new ol.View({
              center: [0, 0],
              zoom: 2
            })
          });

          document.getElementById('set-source').onclick = function() {
            layer.setSource(source);
          };

          document.getElementById('unset-source').onclick = function() {
            layer.setSource(null);
          };
        </script>
      </body>
    </html>