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Usability Performance Discussion
This page will feature ideas for improvement regarding the introspection and change detection central to the extension functionality.
Related discussion: https://github.com/rev087/ng-inspector/issues/85
This problem exists in both ng-inspector and Batarang.
The main issue is that it adds too many watchers. It adds a single deep watch to every scope.
The main issue is that it has to serialize big objects, creates large GC pauses.
In ng-inspector, one thing users requested was that models were initially expanded. This made it easy to (at a quick glance) get a high-level view of the shape of the models on a scope.
However, this has a performance tradeoff. For Batarang, this means sending more info through different contexts. For ng-inspector, this means rendering more often.
Instrumentation should send over enough information to populate the screen in whatever state its in. We can do this by looking at the current viewport to see what things are being viewed.
We can look at scroll position and whether the part of the UI is expanded. Based on this, we can determine which parts of the scope are interesting. ng-hint has a method that's helpful: https://github.com/angular/angular-hint/blob/refactor-all-the-things/src/modules/scopes.js#L24-L48
We should have some apps that we can use as baselines.
The following are sites in the code that are interesting for implementing this strategy in ng-inspector.
This is where instrumentation touches the scope: https://github.com/rev087/ng-inspector/blob/master/src/js/Scope.js#L55
https://github.com/rev087/ng-inspector/blob/master/src/js/InspectorAgent.js#L13
Traverse the scopes here: https://github.com/rev087/ng-inspector/blob/master/src/js/InspectorAgent.js#L80