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JavaScript Academy · Lesson

if/else and switch — core patterns

Write clear conditions with if/else and switch; use guard clauses for early exits.

if/else and switch — core patterns is a free JavaScript Academy lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the JavaScript Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Intro

Goal: Choose the right conditional. Start with if/else, add else if for multiple branches, and use switch for clean value matching.

if/else and switch — core patterns — illustration 1

if/else basics

If the condition is true, run the first block; otherwise run the else block.

// if/else — choose between two paths
const score = 72;

if (score >= 60) {
  console.log("Pass");
} else {
  console.log("Retry");
}
if/else and switch — core patterns — illustration 2

else if chain

Use else if for ordered checks from most specific to least.

// else if — three or more branches
const temp = 18;

if (temp >= 30) {
  console.log("Hot");
} else if (temp >= 15) {
  console.log("Mild");
} else {
  console.log("Cold");
}
if/else and switch — core patterns — illustration 3

switch basics

switch matches exact values. Remember to break to avoid falling through.

// switch — clean matching on a single value
const day = "Mon";

switch (day) {
  case "Mon":
    console.log("Start strong");
    break;
  case "Fri":
    console.log("Finish line");
    break;
  default:
    console.log("Keep going");
}
if/else and switch — core patterns — illustration 4

Guard clause

Use a guard clause to exit early when inputs are not valid; keeps the happy path clear.

// Guard clause — return early for invalid input
function greet(name) {
  if (!name) {
    console.log("Name required");
    return;
  }
  console.log("Hello, " + name + "!");
}

greet("");
greet("Ayla");
if/else and switch — core patterns — illustration 5

Tips & mistakes

Tips:

  • Order checks from most specific to least.
  • Keep conditions short and readable.
  • In switch, include a default case.
if/else and switch — core patterns — illustration 6

switch comparison quiz

Quick check: switch matching.

if/else and switch — core patterns — illustration 7

Recap

Recap: Use if/else for two paths, else if for ordered branches, switch for exact value matches, and guard clauses for early exits.

if/else and switch — core patterns — illustration 8

Frequently asked questions

Is the “if/else and switch — core patterns” lesson free?

Yes — the full text of “if/else and switch — core patterns” is free to read here on the web, and the JavaScript Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the JavaScript Academy course, upgrade to CoddyKit PRO.

What will I learn in “if/else and switch — core patterns”?

Write clear conditions with if/else and switch; use guard clauses for early exits. You practise JavaScript Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start JavaScript Academy?

No prior experience is required. JavaScript Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.

How long does the “if/else and switch — core patterns” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this JavaScript Academy lesson?

Yes. Every JavaScript Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. if/else and switch — core patterns
  2. Loops: for, while, do…while, for…of vs for…in
  3. Early Returns and Guard Clauses
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