KnockoutJS tip : when to use brackets?

I simply love the knockout.JS framework. It makes the migration from silverlight to javascript / html so much more comfortable.

One point of confusion in knockout JS you might feel is when do you have to use brackets in front of observable and when can you ignore them? 

e.g. in the knockout intro tutorial : http://learn.knockoutjs.com/#/?tutorial=intro 

This: 

will work just as well as: 

Then whats the difference?  is actually a function since ko.observable returns a function : 

My solution:
In code ALWAYS use ().You have to, otherwise you will remove the ko.observable function on assignment which is bad. And on reading you would get the function not the value you wanted. 

In simple data-bind attributes NEVER use (). Because it will not work to two way data binding, i.e If I had bound value: firstName() to the input it would not have worked.  

In calculated data-bind attributes e.g. value: firstName() + lastName() , use brackets since you want one way binding and basically running arbitrary javascript :) 

Enjoy! 

Best programming tutorials for JavaScript: With videos!

There is lots you can read about javascript.

But I have always found videos to be a great way to learn real world programming. You get to see people think. You get to see people perform. Great for finding productivity tips that have a HUGE impact.

Here is my playlist for JavaScript (the language) :

Playlist 1:

Some tips: 

Javascript has only one number type
and it is equivalent to double, floating point type
If you are dealing with money, multiply with 100, do arithmetic, divide by 100 :)


And if you cannot get enough, Playlist 2:


You can find all the slides for "Crockford on JavaScript" here : http://www.slideshare.net/douglascrockford/presentations

Enjoy!