wfs t - Using wfs-t in OpenLayers 3?

I'm using OpenLayers-3.6.0 in a web application. I have wfs layer as follow:

var url="http://localhost:8080/geoserver/wfs?&" + 
      "service=wfs&version=1.1.0&request=GetFeature&typeNames=usa:states";
var format = new ol.format.WFS({});
var source = new ol.source.Vector({
    url: 'proxy.cgi?url='+ encodeURIComponent(url),
    format: format
});
layer wfs = new ol.layer.Vector({
    title: 'states',
    source: source

});

I edit this Point layer as follow:

draw = new ol.interaction.Draw({
    source: source,
    type: 'Point'
});

Now I want to save this layer in server side. In OpenLayers-2 we defined a saveStrategy and then call save method of it. It is shown as follows:

var saveStrategy = new OpenLayers.Strategy.Save();


/*
* change layer's features
*/

saveStratefy.save();

How can I do it in OpenLayers-3.6.0?

Answer

Have a look at my blog for a bit on WFS-T. This uses the OL 3.5 library.

https://medium.com/@goldrydigital/wfs-t-with-openlayers-3-16-6fb6a820ac58