Simple One way binding for ng-repeat?

Question

I have read some articles that said ng-repeat would led to poor performance if there is over 2000 items, because there are too many two way binding to watch. I am new to angularjs and have trouble understanding the relationship between ng-repeat and two-way binding:

1. Does ng-repeat (like outputting a list of json objects) necessarily create two way binding?

2. Is there a simple way to do ng-repeat using only one way binding? (preferably do not need external module)

Answer 1

Like user1843640 mentioned, if you are on Angular 1.3, you can use one-time-binding, but, just for clarity, you need to put the :: on all the bindings, not just the repeater. The docs say do this:

<div ng-repeat="item in ::items">{{item.name}}</div>

But, if I count the watchers, this only removed one. To really drop the number of two-way-bindings, place the :: on the bindings within the repeater, like this:

<div ng-repeat="item in ::items">{{::item.name}}</div>

Here are two plunkers that will display the number of watchers:

All Bindings
Repeater Only

Thanks goes out to Miraage for provinding the function to count the watchers https://stackoverflow.com/a/23470578/2200446

Answer 2

For anyone using or upgrading to Angular 1.3 you can now use "one-time binding". For ng-repeat it would look like this:

<div ng-repeat="item in ::items">{{item.name}}</div> 

Notice the ::items syntax.

For more information check the Angular documentation for expressions.