Pattern
Copy-ready to-do list examples with five practical snippets, clear explanations, common mistakes and related JavaScript examples.
This page focuses on small examples that are easy to paste into a test file, understand, and adjust.
5 practical examples
Basic to-do list example
Start with a small function that is easy to test.
function to_do_list() {
const message = 'Example ready';
console.log(message);
}
to_do_list();Use this as a starting point, then rename classes, variables and labels to match your project.
Use to-do list with data
Keep input data separate from the logic so it is easier to reuse.
const items = ['North', 'South', 'East'];
const result = items.map(item => item.toUpperCase());
console.log(result);Use this as a starting point, then rename classes, variables and labels to match your project.
DOM to-do list example
Connect the code to a button or element on the page.
const button = document.querySelector('[data-action]');
button?.addEventListener('click', () => {
document.body.classList.toggle('is-active');
});Use this as a starting point, then rename classes, variables and labels to match your project.
Safe to-do list pattern
Check that elements exist before running browser code.
const target = document.querySelector('[data-target]');
if (target) {
target.textContent = 'Updated from JavaScript';
}Use this as a starting point, then rename classes, variables and labels to match your project.
Reusable to-do list helper
Wrap the pattern in a function so it can be reused in other pages.
function updateText(selector, value) {
const element = document.querySelector(selector);
if (!element) return;
element.textContent = value;
}
updateText('[data-output]', 'Done');Use this as a starting point, then rename classes, variables and labels to match your project.
Common mistakes to avoid
- Copying a snippet without changing class names, selectors, or labels for your page.
- Testing only on a desktop screen and missing mobile behavior.
- Forgetting accessibility details such as labels, focus states, and meaningful text.
FAQ
Can I copy these examples?
Yes. They are written as practical starting points you can copy, study and adapt.
Are these examples beginner-friendly?
Yes. Each page keeps the examples small and explains when the pattern is useful.