脏检查角

Question

I was recently going through a pretty interesting article about data binding in angularJS . I came across a term there : 'Dirty-Checking', which is performed during a $digest operation. The term sounded quite interesting to me but unfortunately, didn't make much sense about what's dirty over there. Does it concern the constant check on some value ?

Answer 1

The term dirty checking refers to the process of comparing values from before a change ( $digest cycle) and after a change.

This blog does a pretty good job explaining the details.

So, when the digest cycle runs in Angular, all the watched scope values (bound to the ui, or using $watch ) are traversed. Each value is resolved and then compared to the value in a previous digest. So, it is checking if the values have been changed (whether they are dirty ).

Hope this helps.