Lumio Learn

JavaScript Course

A practical JavaScript path for people who want to write code, understand browser behavior, and solve real tasks.

Lesson 1 · 10 min

JavaScript Variables and Constants

Use let and const to store values, build strings, and print predictable output.

Beginner
Lesson 2 · 12 min

JavaScript Functions

Write reusable functions, pass arguments, return values, and test the result.

Beginner
Lesson 3 · 14 min

JavaScript Arrays

Store ordered values, transform arrays with map, and filter data for real UI work.

Beginner
Lesson 4 · 14 min

JavaScript Strings

Work with text values, clean user input, build labels, and create URL-friendly slugs.

Beginner
Lesson 5 · 15 min

JavaScript Objects

Group related values into one structure and read properties with clear names.

Beginner
Lesson 6 · 15 min

JavaScript Conditionals

Make decisions with if, else if, and else so code can react to different situations.

Beginner
Lesson 7 · 16 min

JavaScript Loops

Repeat work over a list of values with a for...of loop and calculate a useful result.

Beginner
Lesson 8 · 17 min

JavaScript JSON

Parse JSON text into JavaScript data, update it, and serialize it back into a string.

Beginner
Lesson 9 · 16 min

JavaScript Scope

Understand where variables are visible and why block scope prevents confusing bugs.

Beginner
Lesson 10 · 18 min

JavaScript Errors and try/catch

Handle expected failures with try/catch instead of letting the whole script crash.

Beginner
Lesson 11 · 16 min

JavaScript Destructuring

Pull useful values out of objects and arrays without noisy repeated property access.

Beginner
Lesson 12 · 18 min

JavaScript Promises

Represent work that finishes later and handle the result with then and catch.

Beginner
Lesson 13 · 18 min

JavaScript async and await

Write asynchronous code in a readable top-to-bottom style with async functions and await.

Beginner
Lesson 14 · 16 min

JavaScript Numbers and Math

Use numbers for totals, percentages, rounding, and practical calculations.

Beginner
Lesson 15 · 17 min

JavaScript Dates

Create dates, compare timestamps, and format stable ISO strings.

Beginner
Lesson 16 · 18 min

JavaScript Regular Expressions

Find and validate text patterns with regular expressions and clear match output.

Beginner
Lesson 17 · 16 min

JavaScript Set

Store unique values, remove duplicates, and check membership quickly.

Beginner
Lesson 18 · 17 min

JavaScript Map

Store key-value pairs and count repeated values without awkward object tricks.

Beginner
Lesson 19 · 17 min

JavaScript Optional Chaining

Safely read nested data with ?. and provide fallback values with ?? when something is missing.

Beginner
Lesson 20 · 18 min

JavaScript Spread and Rest

Copy arrays and objects with spread, and collect extra function arguments with rest parameters.

Beginner
Lesson 21 · 19 min

JavaScript Array reduce

Turn an array into one result, such as a total, summary object, or grouped count.

Beginner
Lesson 22 · 20 min

JavaScript Form Validation

Check form-like data, collect friendly error messages, and normalize input before using it.

Beginner
Lesson 23 · 20 min

JavaScript Classes

Group data and behavior into a reusable blueprint with constructor and methods.

Beginner
Lesson 24 · 18 min

JavaScript Truthy and Falsy Values

Understand how JavaScript treats values as true or false inside conditions.

Beginner
Lesson 25 · 18 min

JavaScript Equality and Comparison

Compare values with strict equality, greater-than checks, and clear boolean rules.

Beginner
Lesson 26 · 19 min

JavaScript Callback Functions

Pass a function into another function so code can decide what to do later.

Beginner
Lesson 27 · 18 min

JavaScript find, some, and every

Search arrays and ask yes/no questions with find, some, and every.

Beginner
Lesson 28 · 19 min

JavaScript Array sort

Sort text and numbers with compare functions instead of trusting default string sorting.

Beginner
Lesson 29 · 18 min

JavaScript null and undefined

Understand missing values, intentional empty values, and safe fallback handling.

Beginner
Lesson 30 · 18 min

JavaScript switch Statement

Choose one branch from several named cases with switch, case, break, and default.

Beginner
Lesson 31 · 17 min

JavaScript Template Literals

Build readable strings with backticks, placeholders, and multi-line text.

Beginner
Lesson 32 · 18 min

JavaScript URLSearchParams

Read, update, and generate query strings with URLSearchParams.

Beginner
Lesson 33 · 18 min

JavaScript Debugging with console

Use console output to inspect values, understand program flow, and narrow down mistakes.

Beginner
Lesson 34 · 20 min

JavaScript DOM Basics

Understand what the DOM is and how JavaScript can read elements from a page.

Beginner
Lesson 35 · 21 min

JavaScript querySelector and querySelectorAll

Find one element or many elements with CSS-style DOM selectors.

Beginner
Lesson 36 · 22 min

JavaScript Changing Text and Classes

Update textContent and classList to change what a page says and how it looks.

Beginner
Lesson 37 · 24 min

JavaScript DOM Events

React to clicks with addEventListener and update the page after an event.

Beginner
Lesson 38 · 26 min

JavaScript Form Submit Handling

Handle a form submit event, prevent page reload, read FormData, and validate values.

Beginner
Lesson 39 · 26 min

JavaScript fetch and JSON

Understand the shape of fetch code, async JSON parsing, and error checks without making a real network request.

Beginner
Lesson 40 · 24 min

JavaScript Modules

Learn why code is split into modules and how import/export thinking keeps projects organized.

Beginner
Lesson 41 · 23 min

JavaScript localStorage

Save small browser preferences as strings and read them again later.

Beginner
Lesson 42 · 21 min

JavaScript sessionStorage

Store short-lived tab data and understand how sessionStorage differs from localStorage.

Beginner
Lesson 43 · 32 min

JavaScript Browser Mini Project

Combine DOM selection, events, validation, and localStorage into one small browser feature.

Beginner
Lesson 44 · 30 min

JavaScript Final Recap Project

Review the beginner JavaScript path by combining data, functions, arrays, validation, and rendering decisions.

Beginner