Updating data in canRoute should not removed any properties on target that are not available on source

[mjstahl]

In a donejs application is you have an app.js file that looks like:

import DefineMap from 'can-define/map/';
import route from 'can-route';
import 'can-route-pushstate';
import 'can-stache-bindings';

const ApplicationVM = DefineMap.extend({
  page: {
    type: 'string',
    get(currentPage) {
      return (this.session) ? (currentPage || 'foo') : 'login';
    },
    serialize: true
  },
  session: {
    type: 'any',
  },
});

route.register('{page}');
export default ApplicationVM;

In the console, run can.viewModel('html').session = {}. The expectation is that page would then be equal to foo.

It does not, because https://github.com/canjs/can-route/blob/master/can-route.js#L94 is calling canReflect.update where I think it should be calling canReflect.assign.

[justinbmeyer]

Needs to call update. I think session should be serialize: false

[justinbmeyer]

Needs to call update because if stateful properties in the url are removed when the url changes, they need to be removed from the view model.

[mjstahl]

Got it. That worked.

So what I think is a little wonky about this is:

1. I don't get route properties displayed in the route unless I serialize: true
2. Properties not on the route, but in the object need to be serialize: false otherwise they get deleted.

I think we should pick on and opt in. And in this case, I think that I am specifying a property in route.register (like route.register('{page}');) - page should be displayed in the route without serialize: true.

My preferred approach would be so:

1. If I have properties registered via route.register
2. If I have imported can-route-pushstate

then:

1. I should NOT have to use serialize: true to get property values in the route
2. I should NOT have to use serialize: false to keep properties from getting deleted when I update route.data

[justinbmeyer]

You can use

“*”: {serialize: false}

To change the defaults.

I like the idea of making props identified by register as serialize:true no matter what.

I’m not sure what to do about point number 2. How should we know which props are part of the url and which aren’t if we support urls like /foo/bar?zed=ted ?

[justinbmeyer]

We could show to use serialize:false trick to teach people how to opt in.

[justinbmeyer]

Another way would be to mount to route data to a property within your app vm. This way everything on that will be serialize true. This might be a better idea.

[justinbmeyer]

closing for #170