Technology & Coding

JavaScript Fundamentals

Write, read, and debug real JavaScript: values, functions, data, the DOM, and async code in seven days.

This course is for members

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What you will learn about JavaScript Fundamentals

The 7-day sprint
  1. Values, Variables, and Types. JavaScript programs are built from values, and variables are names you attach to values so you can use them later.
  2. Operators, Coercion, and Truthiness. Operators combine values into new values, and JavaScript will silently convert types along the way unless you control it.
  3. Functions, Scope, and Return Values. A function is a reusable machine that takes inputs, does work, and hands back a value, and where you declare it decides what it can see.
  4. Arrays and Objects. Objects group related values under names and arrays hold ordered lists, and together they model almost all real data.
  5. Control Flow and Iterating Data. Programs choose between paths and repeat work, and for data in arrays the map, filter, and reduce methods express that repetition more clearly than loops.
  6. The DOM and Events. A web page is a tree of objects that JavaScript can read and change, and event listeners let your code react to what the user does.
  7. Asynchronous JavaScript. Slow work like network requests does not block the program; it finishes later, and promises with async and await let you write that clearly.
The 80/20: the 7 concepts that matter most
  • Values, references, and mutation
  • Functions, scope, and closures
  • Modeling data as arrays of objects, then transforming it
  • Truthiness, equality, and coercion
  • The event loop and asynchronous code
  • The DOM as state plus rendering
  • Errors and debugging
The core idea, explained like you are 5

A variable is a name pointing at a value, and understanding what that name actually points at, a copy or a shared thing, explains almost everything else in JavaScript.

Then the quiz and the ladder

10 questions that correct you when you are wrong, and beginner, intermediate, advanced levels, each with a practical exercise.