I've not found an appropriate example in the forums, but I simply want to change different fields as required/not required depending on a list selection. 

I'm using self-hosted Forms v11 update 5. 

LFForm.onFieldChange(() => grantOriginNum(), {fieldId: 45});
function grantOriginNum(){
  //the list selector
  let grantOrigin = LFForm.getFieldValues({fieldId: 45});
  
  if(grantOrigin == 'Federal'){
    LFForm.setFieldValues({fieldId: 38}, "Federal");
    LFForm.changeFieldSettings({fieldId:12}, {required: "true"});
  }
  if(grantOrigin == 'State'){
    LFForm.setFieldValues({fieldId: 38}, "State");
    LFForm.changeFieldSettings({fieldId:43}, {required: "true"});
  }
  if(grantOrigin == 'Other'){
    LFForm.setFieldValues({fieldId: 38}, "Other");
    LFForm.changeFieldSettings({fieldId:46}, {required: "true"});
  }
}