What steps should I take to verify the validity of an Angular form?

Question

What steps should I take to verify the validity of an Angular form?

I am struggling with validating an inscription form in HTML. Despite trying to implement validations, the inputs are still being saved in the database even when they are empty. Here are the validations I want to include:

All inputs are required
Email address should be valid
Name should only contain letters
Password must have a minimum of 8 characters, at least 1 uppercase letter, 1 lowercase letter, and 1 number

Additionally, I would like to display a message under every invalid input using

<div id="na"></div>

. How can I achieve this?

Below is my HTML file:

<h2 class="text-center">Inscription</h2>
<div class="row">
... // (HTML code here)
</div>

Here is my TypeScript file:

import { Component, OnInit } from '@angular/core';
... // (TypeScript code here)

Thank you in advance.

javascript angular typescript forms

Answer 1

Answer №1

this is the code snippet for setting up form validation in Angular:</p>

this.angForm = this.fb.group({
email: ['', Validators.required, Validators.email],
password: ['', Validators.required, Validators.minLength(8), Validators.pattern("(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}")],
name: ['', Validators.required, Validators.pattern('^[a-zA-Z ]*$')],
mobile: [null, Validators.required, Validators.minLength(10), Validators.maxLength(10)]
});

In your HTML file, make sure to include appropriate error messages next to each form field:</p>

<span class="text-danger"
       *ngIf="(angForm.name.touched || submitted) && 
                angForm.name.errors?.required">
            Name is required
</span>
        
<span class="text-danger"
       *ngIf="((angForm.password.touched || submitted) && 
                angForm.password.errors?.required )|| (angForm.invalid && submitted)">
            Password must contain at least one number and one uppercase and lowercase letter, and be at least 8 characters long.
</span>

Ensure that similar error messages are set up for email and mobile fields as well.</p>

For a more detailed guide on how to validate Angular reactive forms, check out this resource:
<a href="https://www.freecodecamp.org/news/how-to-validate-angular-reactive-forms/" rel="nofollow noreferrer">https://www.freecodecamp.org/news/how-to-validate-angular-reactive-forms/</a></p>

Answer 2

this is the code snippet for setting up form validation in Angular:</p>

this.angForm = this.fb.group({
email: ['', Validators.required, Validators.email],
password: ['', Validators.required, Validators.minLength(8), Validators.pattern("(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}")],
name: ['', Validators.required, Validators.pattern('^[a-zA-Z ]*$')],
mobile: [null, Validators.required, Validators.minLength(10), Validators.maxLength(10)]
});

In your HTML file, make sure to include appropriate error messages next to each form field:</p>

<span class="text-danger"
       *ngIf="(angForm.name.touched || submitted) && 
                angForm.name.errors?.required">
            Name is required
</span>
        
<span class="text-danger"
       *ngIf="((angForm.password.touched || submitted) && 
                angForm.password.errors?.required )|| (angForm.invalid && submitted)">
            Password must contain at least one number and one uppercase and lowercase letter, and be at least 8 characters long.
</span>

Ensure that similar error messages are set up for email and mobile fields as well.</p>

For a more detailed guide on how to validate Angular reactive forms, check out this resource:
<a href="https://www.freecodecamp.org/news/how-to-validate-angular-reactive-forms/" rel="nofollow noreferrer">https://www.freecodecamp.org/news/how-to-validate-angular-reactive-forms/</a></p>

Answer 3

Answer №2

reply to Rothitha If you prefer not to utilize the "auxiliary variable" submitted, you can incorporate it in the submit function.

submit(form:FormGroup)
{
   if (form.invalid)
      form.markallAsTouched()
   else
   {
      ..doSomething..
   }
}

To improve error management and get rid of the cumbersome

*ngIf="angForm.get('password').touched && angForm.get('password').touched"

, we can implement a similar technique as Bootstrap for handling errors.

We employ a .css like

.invalid-feedback
{
   display:none
}
.ng-invalid.ng-touched ~ .invalid-feedback
{
  display: block;
}

Along with an HTML structure like

<!--enclose everything within a div-->
<div>

    <!--a label-->
    <label for="email">Email</label>

    <!--an input field-->
    <input id="email" formControlName="email">

    <!--a div with class="invalid-feedback-->
    <div class="invalid-feedback">

        <!--use *ngIf for multiple validators-->
        <div *ngIf="angForm.controls.email.errors?.required">Email is required</div>
        <div *ngIf="angForm.controls.email.errors?.email">Invalid email format</div>
    </div>

</div>

For reference, check out this stackblitz link

Answer 4

reply to Rothitha If you prefer not to utilize the "auxiliary variable" submitted, you can incorporate it in the submit function.

submit(form:FormGroup)
{
   if (form.invalid)
      form.markallAsTouched()
   else
   {
      ..doSomething..
   }
}

To improve error management and get rid of the cumbersome

*ngIf="angForm.get('password').touched && angForm.get('password').touched"

, we can implement a similar technique as Bootstrap for handling errors.

We employ a .css like

.invalid-feedback
{
   display:none
}
.ng-invalid.ng-touched ~ .invalid-feedback
{
  display: block;
}

Along with an HTML structure like

<!--enclose everything within a div-->
<div>

    <!--a label-->
    <label for="email">Email</label>

    <!--an input field-->
    <input id="email" formControlName="email">

    <!--a div with class="invalid-feedback-->
    <div class="invalid-feedback">

        <!--use *ngIf for multiple validators-->
        <div *ngIf="angForm.controls.email.errors?.required">Email is required</div>
        <div *ngIf="angForm.controls.email.errors?.email">Invalid email format</div>
    </div>

</div>

For reference, check out this stackblitz link

What steps should I take to verify the validity of an Angular form?

Answer №1

Answer №2

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