CODEWITHSUNDEEP
javascriptasp.netasp.net-mvcknockout.js
LINQ2Vodka
LINQ2Vodka

Reputation: 3036

Knockout.js performance - how many observables?

I am new to Knockout.js and already like it very much.

Say I'm implementing web blog and want add/edit/delete blog post comments with using of Knockout.js. In purpose of this I define Comment viewmodel with subject, text and tags (in my real application i need much more fields, like 10 to 20).

After the message have been edited by user and posted to server I want to refresh it at the screen with the latest values (including those that came from server - say, timestamp). It appears that I need observable (not just simple) properties for every listed field, otherwise the values will not be refreshed at user's screen after postback.

Now, if I have 20 observables per comment and there are 50? 100? comments on the screen, then will it slow browser down much? What about mobile devices? If so, is there another way to achive what I want?

The other possible option is to use viewmodels only for the comment being edited. In this case I somehow need to "unbind" other viewmodels from html elements - ex., delete it and render again. But here I can't see a nice solution.

Upvotes: 1

Views: 757

Answers (2)

ffflabs
ffflabs

Reputation: 17481

This use case scenario sounds like a perfect match for the mapping plugin:

// Every time data is received from the server:
ko.mapping.fromJS(data, viewModel);

And if you ever get into performance issues, the Viewmodel plugin claims to be several times faster specifically for the task of updating your viewmodel from an updated model.

ko.viewmodel.updateFromModel(viewmodel, updatedModel);

Upvotes: 1

Rowan Freeman
Rowan Freeman

Reputation: 16358

Interesting question.

The short, simple answer is no.

Browser performance is not really an issue unless you are specifically developing an application that is know or expected to be a performance hit.

A browser is well designed to handle very large amounts of data. Be it downloading new data from a server or rendering DOM elements. I would say a browser could handle over 1000 comments (an educated guess).

Take a look at a Google application (such as calendar) - they tend to process huge amounts of data.

Upvotes: 1

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