Revisit forcing to-string conversion for can-maps

[justinbmeyer]

Fixing this:

• Route/Map triggering too many changes canjs#2206

is just plain weird.

Instead of doing this, I think we should take the serialized data, param it, deparam it. If it doesn't match the original serialized data ... we should warn the user what is going on .

This means people won't be able to set numbers and such (without a type converter), but it will eliminate the zaniness that is going on in 3.0 and would carry onto 4.0.

var stringCoercingMapDecorator = function(map) {
	var sym = canSymbol.for("can.route.stringCoercingMapDecorator");
	if(!map.attr[sym]) {
		var attrSuper = map.attr;

		map.attr = function(prop, val) {
			var serializable = this.define === undefined || this.define[prop] === undefined || !!this.define[prop].serialize,
				args;

			if (serializable) { // if setting non-str non-num attr
				args = stringify(Array.apply(null, arguments));
			} else {
				args = arguments;
			}

			return attrSuper.apply(this, args);
		};
		canReflect.setKeyValue(map.attr, sym, true);
	}

	return map;
};

[justinbmeyer]

To be clear ... every time we are going to update the url from route.data changes, I propose that in development mode we do something like:

var serialized = route.data.serialize();
var serializedFromRoute = route.deparam( route.param( serialized) );
if( ! deepEqual(serialized, serializedFromRoute) ) {
  // give a warning about what is different
}