淘汰赛2.2和3中ko.mapping.fromJS方法是否过时？

Question

I'm having a problem to use ko.mapping.fromJS( in knockout. I've been testing on version 2.2 and 3. Anybody else who has had problems? Or are there any other alternatives to updating a instatieted viewmodel?

if (PAGE.blogViewModel == null) {
                    PAGE.blogViewModel = new BlogViewModel(data);
                    ko.applyBindings(PAGE.blogViewModel, document.getElementById("blog_container"));
                } else {
                    ko.fromJSON(data, PAGE.blogViewModel); 
                }

The updating ko.fromJSON(data, PAGE.blogViewModel); does not work.

*TypeError: ko.fromJSON is not a function*

And oddly enough I've used ko.mapping.fromJS( before and it has worked.

ko.mapping.fromJS(data, PAGE.blogViewModel);

TypeError: ko.mapping is undefined

Answer 1

ko.mapping.fromJS is not deprecated because it was never part of the core Knockout library.

The ko.mapping.fromJS is comming from the Knockout Mapping plugin .

You need to download and include it separately in your HTML to use it.

Answer 2

It sounds like you haven't included the ko.mappings-library . Make sure that it is loaded after Knockout is loaded.