OL3: force loading of source

Question

I have a layer with maxResolution set, such that the layer is displayed only when you zoom in at a certain level. My issue is that the layer source data is loaded only when zooming at that level. Is there a way to preload the vector source data?

var source = new ol.source.Vector({
    url: '/mapsource/source.geojson',
    format: new ol.format.GeoJSON()
});

// how do I force loading the source here, and not wait for the map to render at 80 zoom?

var layer = new ol.layer.Vector({
    title: 'Test layer',
    source: source,
    style: my_style,
    maxResolution: 80
});

Answer 1

You can load data over ajax and add to your source.

var source = new ol.source.Vector();

$.getJSON('/mapsource/source.geojson').done(function(data){
    var features = (new ol.format.GeoJSON()).readFeatures(data);
    source.addFeatures(features);
});