Full Stack Web Developer

THEORETICAL RECAP In JavaScript ES6+, you declare variables mainly with two keywords: 'let' and 'const'. Use 'const' when a value must not be reassigned after its initial assignment, and 'let' when the value may change over time. Avoid the older 'var...

JavaScript is the programming language that brings interactivity to web pages. Before writing any logic, you must understand how to store and manipulate data. This is the role of variables and primitive types. This chapter covers the modern way to de...

Welcome to the chapter dedicated to JavaScript ES6+ basics and manipulation of the Document Object Model. This chapter is a decisive step in your journey to becoming a Full Stack Web Developer. Until now, you have discovered how to structure web page...

This chapter closes the foundational section on algorithmics and programming logic. Its purpose is twofold: to assess and consolidate everything you have learned so far (variables, conditions, loops, functions, lists, and time complexity), and to pre...

When you write code, you want it to produce the correct result. But producing the correct result is not enough for a professional developer. You also need your code to run efficiently, especially when it processes large amounts of data. This is where...

## Project overview You will build a command-line cash register program that simulates a real point-of-sale checkout. This mini-project consolidates every core concept you have practiced in the Algorithmics and programming logic chapter: functions, p...

THEORETICAL RECAP Finding the minimum in a list is a fundamental algorithmic pattern you will reuse constantly. The idea is simple: you traverse a list of values once, keeping track of the smallest value seen so far. The correct mental model is that ...

THEORETICAL RECAP A list (also called an array or table) is an ordered collection of values stored under a single name, where each element occupies a position identified by an index. In most programming languages, indexing starts at 0: the first elem...

Until now, you have worked with variables that store a single value at a time: a number, a text string, or a boolean. But real programs often need to handle many values at once. Imagine you want to store the names of thirty students, the prices of on...

Documentation and comments are two closely related practices that make your code understandable, maintainable, and reusable by yourself and by others. After learning to write loops, conditions, and functions, you now need to learn how to explain what...

THEORETICAL RECAP A factorial of a non-negative integer n (written n!) is the product of all positive integers from 1 up to n, with the special rule that 0! equals 1. In programming, the factorial is the classic example used to compare two approaches...

In the previous chapters, you learned to create functions and procedures to organize your code into reusable blocks. Now we go deeper into two fundamental concepts that determine how functions communicate with the rest of the program: the passage of ...

THEORETICAL RECAP A function is a reusable block of code that takes zero or more inputs (called parameters or arguments), performs a task, and often returns a result. The mental model to keep in mind is that of a machine: you feed it raw material (th...

Until now, you have written instructions in a single continuous block: conditions, loops, calculations, all following one another from top to bottom. This works for small exercises, but as soon as a program grows, this approach becomes unmanageable. ...

THEORETICAL RECAP A loop repeats a block of instructions until a condition is met. You have already worked with 'while' loops (repeat as long as a condition is true) and 'for' loops (repeat a known number of times, with a counter). The mental model t...

Nested loops are one of the most powerful tools in programming, but also one of the most dangerous in terms of performance. A nested loop is simply a loop placed inside another loop. You already know how to write a single loop (the 'while' and 'for' ...

THEORETICAL RECAP A factorial of a non-negative integer N, written N!, is the product of all positive integers from 1 up to N. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120. By convention, 0! = 1. This is a perfect problem for the 'for' loop, because you...

Loops let you repeat instructions. But repetition alone is not enough: what matters is what you do during each repetition. Over time, programmers noticed that the same structures come back again and again. These are called loop patterns. Learning the...

THEORETICAL RECAP A 'while' loop repeats a block of instructions as long as a condition remains true. Its structure is simple: you define a starting point (an initialization), a condition that is tested before each iteration, and an update inside the...

In programming, one of the most powerful ideas is the ability to repeat instructions automatically. So far, you have learned how to store data in variables, run instructions in sequence, and make decisions using conditions with IF, AND, OR. Loops add...

THEORETICAL RECAP A program is a sequence of instructions executed in order. To build useful logic, you combine three foundations you have already studied: variables (containers that store data such as numbers, strings or booleans), conditions (IF / ...

Until now, you have learned to write a single condition inside an IF test, using comparison operators such as greater than, less than, or equal to. But in real programs, a single condition is often not enough. You frequently need to check several thi...

THEORETICAL RECAP A conditional structure lets a program make decisions. The core mental model is simple: 'IF a condition is true, THEN execute this block; OTHERWISE execute another block.' A condition is a boolean expression that evaluates to either...

Comparison operators and boolean values are at the heart of every decision your programs will ever make. In the previous chapters, you learned how to store data in variables, perform calculations, and write your first simple conditional test with the...

THEORETICAL RECAP A conditional test (the IF statement) allows a program to make decisions. Instead of executing instructions in a strict linear order, the program evaluates a condition — a boolean expression that is either TRUE or FALSE — and only r...