validation - How can I extend AngularJS model flags on an Angular form? -

angularjs provides call 'model flags' on forms. example, can have formname.$dirty, formname.$invalid, etc. want know how can create own custom flag angularjs forms? high level demonstration or link article sufficient answer.

see here: how-to-add-custom-validation-to-an-angular-js-form.

in short, custom valitation directive example:

app.directive('blacklist', function (){     return {       require: 'ngmodel',       link: function(scope, elem, attr, ngmodel) {           var blacklist = attr.blacklist.split(',');            // dom -> model validation           ngmodel.$parsers.unshift(function(value) {              var valid = blacklist.indexof(value) === -1;              ngmodel.$setvalidity('blacklist', valid);              return valid ? value : undefined;           });            //for model -> dom validation           ngmodel.$formatters.unshift(function(value) {              ngmodel.$setvalidity('blacklist', blacklist.indexof(value) === -1);              return value;           });       }    }; }); 

and it's example of it's usage:

<form name="myform" ng-submit="dosomething()">    <input type="text" name="fruitname" ng-model="data.fruitname" blacklist="coconuts,bananas,pears" required/>    <span ng-show="myform.fruitname.$error.blacklist">       phrase "{{data.fruitname}}" blacklisted</span>    <span ng-show="myform.fruitname.$error.required">required</span>    <button type="submit" ng-disabled="myform.$invalid">submit</button> </form> 

but, again, read referenced question , accepted answer, it's far more complete...