An error occurred while saving the commentKent C. Dodds commented
Hi Ward! BartNet asked me to come on and explain why we're deep watching the model. Here's the code where that happens (for reference): https://github.com/formly-js/angular-formly/blob/master/src/directives/formly-form.js#L114
In prose, angular-formly allows you to dynamically alter the properties of fields. This feature is called expressionProperties (see this egghead.io lesson for more info https://egghead.io/lessons/angularjs-angular-formly-expressionproperties?pl=advanced-angular-forms-with-angular-formly). The expressionProperties are run when any of the model properties change. This is an extremely powerful feature of angular-formly. It also normally results in fewer watches because there's a single watch per form rather than a single watch per expression property.
Based on what you've said though, I don't see this change actually happening anytime soon... People may have to find a way around it...