import { Component ,OnInit } from '@angular/core';
import { FormControl, FormGroup, Validators,FormBuilder } from '@angular/forms';
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent  implements OnInit  {
  title = 'Dunamic validation';
  validationStatus:string = "Validate Email and Address";
  validationTypes:[] = ['Email And Address','Email','Address','None']
  myForm:FormGroup;
  constructor(private fb: FormBuilder){
    this.myForm = this.fb.group({
      'validationType':[],
      'email':[],
      'address1':[]
    })
  }
   ngOnInit() {
       this.myForm.controls['validationType'].valueChanges.subscribe((selectedValidator) => {
         console.log(selectedValidator);
  		  this.updateValidator(selectedValidator);
  	});
  	this.myForm.controls['validationType'].setValue(this.validationTypes[0]);
   }
  updateValidator(validator){
     let validateAddress:boolean = validator === 'Address';
     let validateEmail:boolean = validator === 'Email';
     let validateEmailAndAddress:boolean = validator === 'Email And Address';
     let validateNone:boolean = validator === 'None';
     
    if(validateEmailAndAddress){
       this.myForm.get("email").setValidators([Validators.required,Validators.email]);
       this.myForm.get("address1").setValidators([Validators.required]);
       this.validationStatus = "Validate Email and Address";
    }
    else if(validateAddress){
      this.myForm.get("address1").setValidators([Validators.required]);
       this.myForm.get("email").clearValidators();
     this.validationStatus = "Validate Address";  
    }
    else if(validateEmail){
     this.validationStatus = "Validate Email";  
     this.myForm.get("address1").clearValidators();
    this.myForm.get("email").setValidators([Validators.required]);
    }
    else if(validateNone){
      console.log('clearValidators..')
      this.myForm.get("email").clearValidators();
      this.myForm.get("address1").clearValidators();
    }
    this.myForm.controls["email"].setValue('');
    this.myForm.controls["address1"].setValue('');
    this.myForm.get('email').markAsPristine();
		this.myForm.get('email').markAsUntouched();
  	this.myForm.get('email').updateValueAndValidity();
  	this.myForm.get('address1').markAsPristine();
		this.myForm.get('address1').markAsUntouched();
  	this.myForm.get('address1').updateValueAndValidity();
  }
}


/*
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
import { NgModule }       from '@angular/core';
import { BrowserModule }  from '@angular/platform-browser';
import { FormsModule,ReactiveFormsModule }    from '@angular/forms';

import { AppComponent }         from './app.component';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule
  ],
  declarations: [
    AppComponent
  ],
  bootstrap: [ AppComponent ]
})
export class AppModule { }


/*
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
/* AppComponent's private CSS styles */
h1 {
  font-size: 1.2em;
  color: #999;
  margin-bottom: 0;
}
h2 {
  font-size: 2em;
  margin-top: 0;
  padding-top: 0;
}
nav a {
  padding: 5px 10px;
  text-decoration: none;
  margin-top: 10px;
  display: inline-block;
  background-color: #eee;
  border-radius: 4px;
}
nav a:visited, a:link {
  color: #607D8B;
}
nav a:hover {
  color: #039be5;
  background-color: #CFD8DC;
}
nav a.active {
  color: #039be5;
}


/*
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
<h1>Angular Reactive form - Dynamic validation </h1>
<br>
<form>
  <div [formGroup]="myForm">
    <div class="form-row">
    <div class="form-group col-md-6">
      <label for="validationType">Controls to Validate (Required Filed Validator)</label>
      <select class="form-control" id="validationType" formControlName="validationType" >
                                     <option *ngFor="let validation of validationTypes" [ngValue]="validation">
                                         {{validation}}
                                       </option>
                                </select>
    </div>
   </div>
  <div class="form-row" [ngClass]="{'has-danger': (myForm.get('email').hasError('required') || myForm.get('email').hasError('email')) && myForm.get('email').touched}">
    <div class="form-group col-md-6">
      <label for="email">Email</label>
      <input type="email" class="form-control" id="email" [(ngModel)]="email"  formControlName="email" placeholder="Email">
      <p *ngIf="myForm.get('email').hasError('required') && myForm.get('email').touched"><span class="form-control-feedback">Email is Required Field</span></p>
      <p *ngIf="!myForm.get('email').hasError('required') && myForm.get('email').hasError('email') && myForm.get('email').touched"><span class="form-control-feedback">Please enter valid Email address</span></p>     
    </div>

   </div>
   <div class="form-row"  [ngClass]="{'has-danger': myForm.get('address1').hasError('required') && myForm.get('address1').touched}">
  <div class="form-group  col-md-6">
    <label for="address1">Address</label>
    <input type="text" class="form-control" id="address1" formControlName="address1"  [(ngModel)]="address1" placeholder="1234 Main St">
    <p *ngIf="myForm.get('address1').hasError('required') && myForm.get('address1').touched"><span class="form-control-feedback">Address is Required Field</span></p>
  </div>
</div>
   <div class="form-row">
  <div class="form-group  col-md-6">
    <button type="text" class="btn btn-primary" id="btn" [disabled]="!myForm.valid">Submit</button>
  </div>
</div>
</div>
<span *ngIf="!myForm.valid" class="alert alert-success">Submit button is <strong>disabled..</strong></span>
<span  *ngIf="myForm.valid" class="alert alert-success">Submit button is <strong>enabled..</strong></span>
</form>

import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { AppModule } from './app/app.module';




platformBrowserDynamic().bootstrapModule(AppModule);


/*
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
/* Master Styles */
h1 {
  color: #369;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 250%;
}
h2, h3 {
  color: #444;
  font-family: Arial, Helvetica, sans-serif;
  font-weight: lighter;
}
body {
  margin: 2em;
}
body, input[text], button {
  color: #888;
  font-family: Cambria, Georgia;
}
a {
  cursor: pointer;
  cursor: hand;
}
button {
  font-family: Arial;
  background-color: #eee;
  border: none;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
  cursor: hand;
}
button:hover {
  background-color: #cfd8dc;
}
button:disabled {
  background-color: #eee;
  color: #aaa;
  cursor: auto;
}

/* Navigation link styles */
nav a {
  padding: 5px 10px;
  text-decoration: none;
  margin-right: 10px;
  margin-top: 10px;
  display: inline-block;
  background-color: #eee;
  border-radius: 4px;
}
nav a:visited, a:link {
  color: #607D8B;
}
nav a:hover {
  color: #039be5;
  background-color: #CFD8DC;
}
nav a.active {
  color: #039be5;
}

/* everywhere else */
* {
  font-family: Arial, Helvetica, sans-serif;
}


/*
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Tour of Heroes</title>
  <script>document.write('<base href="' + document.location + '" />');</script>

  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" type="image/x-icon" href="favicon.ico">
 <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">
    <link rel="stylesheet" href="styles.css">
    <script src="https://unpkg.com/core-js/client/shim.min.js"></script>
    <script src="https://unpkg.com/zone.js@0.7.4?main=browser"></script>
    <script src="https://unpkg.com/systemjs@0.19.39/dist/system.src.js"></script>
    <script src="systemjs.config.js"></script>
    <script>
      System.import('main.js').catch(function(err){ console.error(err); });
    </script>
    </head>
    
<body>
  <app-root></app-root>
  <script src="https://code.jquery.com/jquery-3.1.1.slim.min.js" integrity="sha384-A7FZj7v+d/sdmMqp/nOQwliLvUsJfDHW+k9Omg/a/EheAdgtzNs3hpfag6Ed950n" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js" integrity="sha384-DztdAPBWPRXSA/3eYEEUWrWCy7G5KFbe8fFjk5JAIxUYHKkDx6Qin1DkWx51bBrb" crossorigin="anonymous"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js" integrity="sha384-vBWWzlZJ8ea9aCX4pEW3rVHjgjt7zpkNpZk+02D9phzyeVkE+jo0ieGizqPLForn" crossorigin="anonymous"></script>
</body>

</html>


<!-- 
Copyright 2017 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
-->
/**
 * WEB ANGULAR VERSION
 * (based on systemjs.config.js in angular.io)
 * System configuration for Angular samples
 * Adjust as necessary for your application needs.
 */
(function (global) {
  System.config({
    // DEMO ONLY! REAL CODE SHOULD NOT TRANSPILE IN THE BROWSER
    transpiler: 'ts',
    typescriptOptions: {
      // Copy of compiler options in standard tsconfig.json
      "target": "es5",
      "module": "commonjs",
      "moduleResolution": "node",
      "sourceMap": true,
      "emitDecoratorMetadata": true,
      "experimentalDecorators": true,
      "lib": ["es2015", "dom"],
      "noImplicitAny": true,
      "suppressImplicitAnyIndexErrors": true
    },
    meta: {
      'typescript': {
        "exports": "ts"
      }
    },
    paths: {
      // paths serve as alias
      'npm:': 'https://unpkg.com/'
    },
    // map tells the System loader where to look for things
    map: {
      // our app is within the app folder
      'app': 'app',

      // angular bundles
      '@angular/animations': 'npm:@angular/animations/bundles/animations.umd.js',
      '@angular/animations/browser': 'npm:@angular/animations/bundles/animations-browser.umd.js',
      '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
      '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
      '@angular/common/http': 'npm:@angular/common/bundles/common-http.umd.js',
      '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
      '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
      '@angular/platform-browser/animations': 'npm:@angular/platform-browser/bundles/platform-browser-animations.umd.js',
      '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
      '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
      '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
      '@angular/router/upgrade': 'npm:@angular/router/bundles/router-upgrade.umd.js',
      '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
      '@angular/upgrade': 'npm:@angular/upgrade/bundles/upgrade.umd.js',
      '@angular/upgrade/static': 'npm:@angular/upgrade/bundles/upgrade-static.umd.js',

      // other libraries
      'rxjs':                      'npm:rxjs@5.5.2',
      'rxjs/operators':            'npm:rxjs@5.5.2/operators/index.js',
      'tslib':                     'npm:tslib/tslib.js',
      'angular-in-memory-web-api': 'npm:angular-in-memory-web-api@0.4/bundles/in-memory-web-api.umd.js',
      'ts':                        'npm:plugin-typescript@5.2.7/lib/plugin.js',
      'typescript':                'npm:typescript@2.4.2/lib/typescript.js',

    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: './main.ts',
        defaultExtension: 'ts',
        meta: {
          './*.ts': {
            loader: 'systemjs-angular-loader.js'
          }
        }
      },
      rxjs: {
        defaultExtension: 'js'
      }
    }
  });

})(this);

/*
Copyright 2016 Google Inc. All Rights Reserved.
Use of this source code is governed by an MIT-style license that
can be found in the LICENSE file at http://angular.io/license
*/
var templateUrlRegex = /templateUrl\s*:(\s*['"`](.*?)['"`]\s*)/gm;
var stylesRegex = /styleUrls *:(\s*\[[^\]]*?\])/g;
var stringRegex = /(['`"])((?:[^\\]\\\1|.)*?)\1/g;

module.exports.translate = function(load){
  if (load.source.indexOf('moduleId') != -1) return load;

  var url = document.createElement('a');
  url.href = load.address;

  var basePathParts = url.pathname.split('/');

  basePathParts.pop();
  var basePath = basePathParts.join('/');

  var baseHref = document.createElement('a');
  baseHref.href = this.baseURL;
  baseHref = baseHref.pathname;

  if (!baseHref.startsWith('/base/')) { // it is not karma
    basePath = basePath.replace(baseHref, '');
  }

  load.source = load.source
    .replace(templateUrlRegex, function(match, quote, url){
      var resolvedUrl = url;

      if (url.startsWith('.')) {
        resolvedUrl = basePath + url.substr(1);
      }

      return 'templateUrl: "' + resolvedUrl + '"';
    })
    .replace(stylesRegex, function(match, relativeUrls) {
      var urls = [];

      while ((match = stringRegex.exec(relativeUrls)) !== null) {
        if (match[2].startsWith('.')) {
          urls.push('"' + basePath + match[2].substr(1) + '"');
        } else {
          urls.push('"' + match[2] + '"');
        }
      }

      return "styleUrls: [" + urls.join(', ') + "]";
    });

  return load;
};