import Map from 'ol/Map';
import View from 'ol/View';
import {platformModifierKeyOnly} from 'ol/events/condition';
import GeoJSON from 'ol/format/GeoJSON';
import ExtentInteraction from 'ol/interaction/Extent';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
import {OSM, Vector as VectorSource} from 'ol/source';

const vectorSource = new VectorSource({
  url: 'data/geojson/countries.geojson',
  format: new GeoJSON()
});

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

const extent = new ExtentInteraction({
  condition: platformModifierKeyOnly
});
map.addInteraction(extent);
extent.setActive(false);

//Enable interaction by holding shift
window.addEventListener('keydown', function(event) {
  if (event.keyCode == 16) {
    extent.setActive(true);
  }
});
window.addEventListener('keyup', function(event) {
  if (event.keyCode == 16) {
    extent.setActive(false);
  }
});