angular form submit validation code example

Example 1: custom validator

import {AbstractControl, ValidatorFn} from '@angular/forms';

export function blue(): ValidatorFn {  
    return (control: AbstractControl): { [key: string]: any } | null =>  
        control.value?.toLowerCase() === 'blue' 
            ? null : {wrongColor: control.value};
}
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Example 2: angularjs form validation on submit

<div class="container" ng-app>

  <h1><span><img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/15309/angular-logo.svg" alt="Angular.js Logo" /></span> Angular.js - Web Form</h1>

  <form role="form" name="form" id="contact-form" novalidate>
    <div class="form-group">
      <label for="FirstName">First name</label>
      <input type="text" class="form-control" name="FirstName" id="FirstName" placeholder="enter first name" ng-model="firstName" required>
    </div>

    <div class="form-group">
      <label for="LastName">Last Name</label>
      <input type="text" class="form-control" name="LastName" id="LastName" placeholder="enter last name" ng-model="lastName" required>
    </div>

    <div class="form-group">
      <label for="EmailAddress">Email address</label>
      <input type="email" class="form-control" id="EmailAddress" name="EmailAddress" placeholder="enter email" ng-model="emailAddress" ng-model-options="{ updateOn: 'blur' }" required>
    </div>

    <div class="checkbox">
      <label>
        <input type="checkbox" required> Check me out
      </label>
    </div>


    <button type="submit" class="btn btn-default" ng-disabled="form.$invalid">Submit</button>

  </form>

</div>

Example 3: validation minlength angular

Validators.minLength(9)

Example 4: formgroup check if valid

form: FormGroup;

onSubmit(){
    //checks if form is valid
       if( this.form.valid){
          //more code here
        }
}