Frontend Mentor - Age calculator app solution

This is a solution to the Age calculator app challenge on Frontend Mentor. Frontend Mentor challenges help you improve your coding skills by building realistic projects.

Table of contents

• Overview
  • The challenge
  • Screenshot
  • Links
• My process
  • Built with
  • What I learned
  • Useful resources
• Author

Overview

The challenge

Users should be able to:

• View an age in years, months, and days after submitting a valid date through the form
• Receive validation errors if:
  • Any field is empty when the form is submitted
  • The day number is not between 1-31
  • The month number is not between 1-12
  • The year is in the future
  • The date is invalid e.g. 31/04/1991 (there are 30 days in April)
• View the optimal layout for the interface depending on their device's screen size
• See hover and focus states for all interactive elements on the page
• Bonus: See the age numbers animate to their final number when the form is submitted

Screenshot

Links

• Solution URL: Frontend Mentor
• Live Site URL: GitHub Pages

My process

Built with

• Semantic HTML5 markup
• CSS custom properties
• CSS Grid
• Mobile-first workflow
• ES6
• Constrain Validation API

What I learned

In this challenge I had the opportunity to practice in more depth CSS Grid, I could also explore the Constrain Validation API to learn more about form validation in the browser and add custom messages to input errors, and also test new CSS features like :has.

<div class="field">
  <label>Name</label>
  <input type="text" name="name" id="name" required />
  <small><!-- Error is showed here--></small>
</div>

.field:has(small:not(:empty)) {
  label {
    color: red;
  }
  input {
    border-color: red;
  }
}

const name = document.getElementById('name');

if (name.validity.valueMissing) {
  name.setCustomValidity('This field is required');
} else {
  name.setCustomValidity('');
}

name.nextElementSibling.textContent = name.validationMessage;

Useful resources

• Client-side form validation
• JavaScript
• Learn JavaScript Form Validation
• JavaScript Date Comparison
• Form Validation, Florin Pop

Author

• LinkedIn - Raúl Barrera
• CodePen - Raúl Barrera
• Frontend Mentor - @raubaca