change id to _id for rest backend

thank you so much for your help gartneriet.
thats exactly the piece i was missing. i did not know how to extend a proxy and you showed me.
after thinking about the problem some more i realized that i actually only need to change the _id to id when data is loaded from the server. everything else works afterwards, because webix is happy to have an ‘id’. this is the code i’m using:

    webix.proxy.mongo = webix.extend({
    $proxy: true,
    load: function(view, callback) {
      var url;
      url = this.source;
      return webix.ajax().get(url).then(function(res) {
        var data;
        data = res.json().map(function(item) {
          item.id = item._id;
          delete item._id;
          return item;
        });
        return webix.ajax.$callback(view, callback, {
          data: data
        });
      });
    }
    }, webix.proxy.rest);

it would have taken me hours without your great tip.

have a great day

metta