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mediumMachine Coding

Build a Form with validation

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01

Understand the problem

Build a contact form with field-level and submit validation.

ReactFormsValidation
02

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03

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Building a Form with Validation in React

Mental model: Keep values, errors, and touched as three maps. Validation is a pure function values -> errors. Show a field's error only once it's been touched (or after a submit attempt). Submit is blocked while any error exists. This separates what's wrong fro

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04

React solution

Complete solutionRun Playground
import React from 'react';
import ValidatedForm from './src/ValidatedForm';

export default function App() {
  return (
    <div style={{ fontFamily: 'sans-serif', padding: 20 }}>
      <h1>Form Validation Demo</h1>
      <ValidatedForm />
    </div>
  );
}
05

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