Imagine you are inserting 100 items into an observable array. More often than not, you don’t need each subscriber to recalculate it’s dependencies 100 items, and UI to be reacting 100 times. Instead, once should just fine.

To do this, you can always modify the underlying array instead of the observableArray directly, since observableArray concept is just a function wrapper around the traditional JS array. After you are done with the array manipulation, you can then notify all the subscribers that the array has changed its state.
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In this example. we are using KO extensions to push all values received via XHR call into the underlying array, and then notifying the subscribers using valueHasMutated().

Labels: javascript, knockout