If/Else & Conditionals

const score = 78;

if (score >= 90) {
  console.log("A — Excellent");
} else if (score >= 75) {
  console.log("B — Good");
} else if (score >= 60) {
  console.log("C — Pass");
} else {
  console.log("F — Try again");
}
// Output: B — Good

// Simple if without else
const isLoggedIn = true;
if (isLoggedIn) {
  showDashboard();
}

// condition ? valueIfTrue : valueIfFalse
const age = 20;
const status = age >= 18 ? "adult" : "minor";
// "adult"

// Great for JSX and template literals
const greeting = isLoggedIn ? "Welcome back!" : "Please log in";

// Can be nested (but keep it readable)
const grade = score >= 90 ? "A" : score >= 75 ? "B" : score >= 60 ? "C" : "F";

const day = "Monday";

switch (day) {
  case "Monday":
  case "Tuesday":
  case "Wednesday":
  case "Thursday":
  case "Friday":
    console.log("Weekday");
    break;  // without break, execution falls through to next case
  case "Saturday":
  case "Sunday":
    console.log("Weekend");
    break;
  default:
    console.log("Unknown day");
}