javascript - Angular2 reactive form confirm equality of values

Question

I am trying to create an Angular2 Reactive form where I have to confirm the email address entered by the user. Here is a link to the plunker

import { Component, OnInit } from '@angular/core';
import { FormControl, FormGroup, Validators } from '@angular/forms';
import { User } from './signup.interface';

@Component({
selector: 'signup-form',
template: `
    <form novalidate (ngSubmit)="onSubmit(user)" [formGroup]="user">
    <label>
        <span>Full name</span>
        <input type="text" placeholder="Your full name" formControlName="name">
    </label>
    <div class="error" *ngIf="user.get('name').touched && user.get('name').hasError('required')">
        Name is required
    </div>
    <div class="error" *ngIf="user.get('name').touched && user.get('name').hasError('minlength')">
        Minimum of 2 characters
    </div>
    <div formGroupName="account">
        <label>
        <span>Email address</span>
        <input type="email" placeholder="Your email address" formControlName="email">
        </label>
        <div
        class="error"
        *ngIf="user.get('account').get('email').hasError('required') && user.get('account').get('email').touched">
        Email is required
        </div>
        <label>
        <span>Confirm address</span>
        <input type="email" placeholder="Confirm your email address" formControlName="confirm">
        </label>
        <div
        class="error"
        *ngIf="user.get('account').get('confirm').hasError('required') && user.get('account').get('confirm').touched">
        Confirming email is required
        </div>
    </div>
    <button type="submit" [disabled]="user.invalid">Sign up</button>
    </form>
`
})
export class SignupFormComponent implements OnInit {
  user: FormGroup;
  constructor() {}
  ngOnInit() {
    this.user = new FormGroup({
    name: new FormControl('', [Validators.required, Validators.minLength(2)]),
      account: new FormGroup({
        email: new FormControl('', Validators.required),
        confirm: new FormControl('', Validators.required)
      })
    });
  }
  onSubmit({ value, valid }: { value: User, valid: boolean }) {
    console.log(value, valid);
  }
}

I want to show an error when these 2 email fields mismatch.

How can I create such a validation for this behaviour using reactive forms in angular2 ?

I have seen a post which does this using template driven approach here, but I was not able to figure out how I could do it using reactive form approach.

Answer 1

I have done password matching using reactive forms. you can change it for email. Just change validator for emails in place of password. both are string everything else is same and put passwordmatch error in email.It will work

app.module.ts

Add these into your app.module.ts file to use reactive forms

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
     ]
  providers: [],
  bootstrap: [
    AppComponent
   ]
  })
export class AppModule {}

app.component.ts

import { Component,OnInit } from '@angular/core';
import template from './add.component.html';
import { FormGroup,FormBuilder,Validators } from '@angular/forms';
import { matchingPasswords } from './validators';
@Component({
    selector: 'app',
    template
})
export class AppComponent implements OnInit {
    addForm: FormGroup;
    constructor(private formBuilder: FormBuilder) {
    }
    ngOnInit() {

    this.addForm = this.formBuilder.group({
            username: ['', Validators.required],
            email: ['', Validators.required],
            role: ['', Validators.required],
            password: ['', Validators.required],
            password2: ['', Validators.required] }, 
          { validator: matchingPasswords('password', 'password2') <-- replace args with email_1 and email_2
        })
    };

addUser() {
        if (this.addForm.valid) {
            var adduser = {
                username: this.addForm.controls['username'].value,
                email: this.addForm.controls['email'].value,
                password: this.addForm.controls['password'].value,
                profile: {
                    role: this.addForm.controls['role'].value,
                    name: this.addForm.controls['username'].value,
                    email: this.addForm.controls['email'].value
                }
            };
          console.log(adduser);// adduser var contains all our form values. store it where you want 
            this.addForm.reset();// this will reset our form values to null 
        }
    }  
}

app.component.html

<div>
  <form [formGroup]="addForm">
   <input type="text" placeholder="Enter username" formControlName="username" />
   <input type="text" placeholder="Enter Email Address" formControlName="email"/>
   <input type="password" placeholder="Enter Password" formControlName="password" />
   <input type="password" placeholder="Confirm Password" name="password2" formControlName="password2"/>
   <div class='error' *ngIf="addForm.controls.password2.touched">
    <div class="alert-danger errormessageadduser" *ngIf="addForm.hasError('mismatchedPasswords')">                                  Passwords do not match
  </div>
</div>
<select name="Role" formControlName="role">
    <option value="admin" >Admin</option>
    <option value="Accounts">Accounts</option>
    <option value="guest">Guest</option>
</select>
<br/>
<br/>
<button type="submit" (click)="addUser()"><span><i class="fa fa-user-plus" aria-hidden="true"></i></span> Add User </button>
</form>
</div>

validators.ts

export function matchingPasswords(passwordKey: string, confirmPasswordKey: string) {
    return (group: ControlGroup): {
        [key: string]: any
    } => {
        let password = group.controls[passwordKey];
        let confirmPassword = group.controls[confirmPasswordKey];

        if (password.value !== confirmPassword.value) {
            return {
                mismatchedPasswords: true
            };
        }
    }
}