Building Multi-Branch Logic with JavaScript switch

switch (expression) {
  case value1: // runs when expression === value1    break;
  case value2: // runs when expression === value2    break;
  default: // runs when NOTHING matches
}

let day = 3;
switch (day) {
  case 1: console.log("Monday 🌅");
  break;
  case 2: console.log("Tuesday 📅");
  break;
  case 3: console.log("Wednesday 🐪");
  // ← MATCH! This runs    break;                          // ← and this stops everything  case 4:    console.log("Thursday 🌤️");    break;  default:    console.log("Unknown day 🤷");}

switch ("1") {
  case 1: console.log("Number one");
  break;
  default: console.log("No match!");
}// Output: "No match!" — the STRING "1" !== the NUMBER 1 😮

let grade = "B";
switch (grade) {
  case "A": console.log("Excellent! 🏆");
  // 😱 no break!
  case "B": console.log("Great! 🎉");
  // 😱 no break!
  case "C": console.log("Good 👍");
  break;
  default: console.log("Keep going! 💪");
}

Great! 🎉Good 👍

let month = "February";
let days;
switch (month) {
  case "January": case "March": case "May": case "July": case "August": case "October": case "December": days = 31;
  // all 7 cases share THIS code!
  break;
  case "April": case "June": case "September": case "November": days = 30;
  break;
  case "February": days = 28;
  // (leap years aside 😄)
  break;
  default: days = "unknown";
}console.log(`${month} has ${days} days.`);
// February has 28 days.

// 😩 The painful alternative:
if (month === "January" || month === "March" || month === "May" || month === "July" || month === "August" || month === "October" || month === "December") {
  days = 31;
}// …yikes.

// ✅ switch's home turf — exact matches on ONE value:switch (httpStatus) {  case 200: console.log("OK ✅"); break;  case 404: console.log("Not Found 🔍"); break;  case 500: console.log("Server Error 💥"); break;}
// ❌ switch CAN'T do this — ranges need if…else:if (score >= 90) { /* A */ }else if (score >= 75) { /* B */ }

let score = 82;
switch (true) {
  case score >= 90: console.log("A 🏆");
  break;
  case score >= 75: console.log("B 🎉");
  break;
  // ← runs  default:    console.log("Keep going 💪");}

let command = "/help";
switch (command) {
  case "/start": console.log("🤖 Bot started!");
  break;
  case "/help": console.log("🤖 Commands: /start /help /joke /quit");
  break;
  case "/joke": console.log("🤖 Why do programmers prefer dark mode? Light attracts bugs! 🐛");
  break;
  case "/quit": console.log("🤖 Goodbye! 👋");
  break;
  default: console.log("🤖 Unknown command — try /help");
}

let key = "ArrowUp";
switch (key) {
  case "ArrowUp": movePlayer(0, -1);
  break;
  case "ArrowDown": movePlayer(0, 1);
  break;
  case "ArrowLeft": movePlayer(-1, 0);
  break;
  case "ArrowRight": movePlayer(1, 0);
  break;
  case " ": jump();
  break;
  default: // ignore other keys
}

let role = "editor";
switch (role) {
  case "admin": console.log("🔑 Full access: create, edit, delete, manage users");
  break;
  case "editor": console.log("✏️ Can create and edit content");
  break;
  case "viewer": console.log("👀 Read-only access");
  break;
  default: console.log("🚫 No access — contact admin");
}

// 📅 Day Planner — switch with grouping + default
let day = "Saturday";
let plan;
let emoji;
switch (day.toLowerCase()) {
  // normalize input — "saturday" matches too!
  case "monday": plan = "Team meeting + code review";
  emoji = "💼";
  break;
  case "tuesday": case "thursday": plan = "Deep work — JavaScript practice";
  // grouped cases!
  emoji = "💻";
  break;
  case "wednesday": plan = "Midweek break — light tasks only";
  emoji = "🌿";
  break;
  case "friday": plan = "Deploy day + weekly wrap-up";
  emoji = "🚀";
  break;
  case "saturday": case "sunday": plan = "Weekend! Rest and recharge";
  // grouped cases!
  emoji = "🏖️";
  break;
  default: plan = "Unknown day — check your spelling";
  emoji = "🤷";
}console.log(`${emoji} ${day}: ${plan}`);