angular-formly provides a very simple API to dynamically change properties of your field (like disabled, hidden, and required) using the powerful expressionProperties property on your field.
One important thing to note is that because of how ng-if works, using
expressionProperties to hide a field can yield unexpected results. In the latest version of angular-formly (as of yesterday, it's still beta) you can specify a
hideExpression instead. See this example