#form-validation code explainers

javascript

const form = document.querySelector('#signup-form');
const password = form.querySelector('#password');
const confirm = form.querySelector('#confirm-password');
const submit = form.querySelector('button[type="submit"]');

Live password-match validation in the DOM

form-validation dom-events accessibility

Intermediate 6 steps

python

from flask import Blueprint, render_template, request, redirect, url_for, flash
from werkzeug.security import check_password_hash
 
from .models import User, db

A change-email route in Flask

blueprints form-validation password-hashing

Intermediate 8 steps

javascript

import { useState } from 'react';
 
const steps = ['account', 'profile', 'review'];

Building a multi-step form wizard hook in React

custom-hooks form-validation state-management

Intermediate 9 steps

javascript

import { useState } from "react";
 
const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

Building a validated signup form in React

form-validation controlled-components state-management

Intermediate 10 steps

typescript

import { Component, computed, inject, signal } from '@angular/core';
import { FormBuilder, ReactiveFormsModule, Validators } from '@angular/forms';
import { CommonModule } from '@angular/common';

Building a signup stepper in Angular

signals reactive-forms form-validation

Intermediate 10 steps

javascript

'use server'
 
import { z } from 'zod'
import { redirect } from 'next/navigation'

How a Next.js Server Action validates a form

server-actions form-validation zod

Intermediate 7 steps

python

from flask import Blueprint, render_template, redirect, url_for, flash
from flask_login import login_required, current_user
from flask_wtf import FlaskForm
from wtforms import StringField, TextAreaField, SubmitField

Handling a post form with a Flask Blueprint

blueprints form-validation post-redirect-get

Intermediate 7 steps

typescript

type SignupInput = {
  email: string;
  password: string;
  confirmPassword: string;

How a typed signup validator collects errors

form-validation type-safety regex

Intermediate 9 steps

rust

use axum::{extract::Form, http::StatusCode, response::{IntoResponse, Response}, Json};
use serde::Deserialize;
use serde_json::json;
use std::collections::HashMap;

Validating a signup form in Axum

form-validation deserialization error-handling

Intermediate 8 steps