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Generate functions that can not be observed.
ObservationRecorder.ignore(fn)
.ignore creates a function that, when called, will prevent observations from
being added. Notice that the observation record returned by stop
has no dependencies:
const fn = ObservationRecorder.ignore( function() {
// This will be ignored
ObservationRecorder.add( obj, "prop1" );
} );
OvervationRecorder.start();
fn();
ObservationRecorder.stop(); //-> {
// keyDependencies: {},
// valueDependencies: {}
// }
Parameters
- fn
{function}:Any function that contains potential calls to add.
Returns
{function}:
A function that is free of observation side-effects.
Use Cases
Some code should not be observable to utilities like can-observation. An example is a can-stache
template. Templates manage observability themselves. So can-stache returns renderer functions wrapped with
.ignore.
Another common place that often needs to be ignored is complex initialization code. Say for example, you had a setter that created an object and then read some of its properties like:
{
set prop( value ) {
const thing = new Thing( value );
if ( !thing.someObservableProperty ) {
thing.someObservableProperty = "VALUE";
}
return thing;
}
}
We wouldn't want this setter to be observed by something, because it's possible that the reading and
setting of someObservableProperty will cause an infinite loop.