Edit

Worker

This example should be deleted.

When you move the map, a message is sent to a worker. In response, the worker sends a message back with the version identifier.

Copy 
index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Worker</title>
    <!-- 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>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script src="index.js"></script>
  </body>
</html>
Copy 
index.jsimport 'ol/ol.css';
/* eslint-disable no-console */

import Map from 'ol/Map';
import View from 'ol/View';
import TileLayer from 'ol/layer/Tile';
import OSM from 'ol/source/OSM';
import {create as createVersionWorker} from 'ol/worker/version';


var map = new Map({
  layers: [
    new TileLayer({
      source: new OSM()
    })
  ],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 2
  })
});

var worker = createVersionWorker();
worker.addEventListener('error', function(error) {
  console.error('worker error', error);
});

worker.addEventListener('message', function(event) {
  console.log('message from worker:', event.data);
});

map.on('moveend', function(event) {
  var state = event.frameState.viewState;
  worker.postMessage({zoom: state.zoom, center: state.center});
});
Copy 
package.json{
  "name": "worker",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}