import {
  MatButtonModule,
  MatCheckboxModule
} from "@angular/material";

import {MatButtonModule, MatCheckboxModule} from '@angular/material';

@NgModule({
  imports: [MatButtonModule, MatCheckboxModule],
  exports: [MatButtonModule, MatCheckboxModule],
})
export class MyOwnCustomMaterialModule { }

export class EqualValidatorDirective implements Validator {
  constructor(@Attribute("compare-to") public compareToControl: string) {}

export class EqualValidatorDirective implements Validator {
  constructor() {}
  @Input('compare-to') compareToControl: string;
  ///...
}

(function (app) {
    'use strict';

    function blackList() {
        return {
            require: 'ngModel',
            link: function (scope, elem, attr, ngModel) {
                var blacklist = attr.blackList.split(',');

                ngModel.$validators.blackList = function (modelValue) {
                    if (modelValue == undefined)
                        return 0;
                    var valid = blacklist.indexOf(modelValue.toString()) === -1;
                    return valid;
                };
            }
        };
    };

    app.directive("blackList", blackList);
})(angular.module('core'));

<div [class.has-error]="blackList">
    <label>Primary Language</label>
    <select name="primaryLanguage" ngModel blackList='default' #primaryLanguage="ngModel">
          <option value="default">Select a Language...</option>
          <option *ngFor="let lang of languages">
            {{ lang }}
          </option>
      </select>
      <small [hidden]="primaryLanguage.valid">
        Not Valid
      </small>
  </div>

<md-tab-group>
        <md-tab label="Tab 1">Content 1</md-tab>
        <md-tab label="Tab 2">Content 2</md-tab>
</md-tab-group>