Control Flow & Functions

JavaScript's if / else if / else and for / while loops work as you'd expect. Functions can be written the classic way, or as modern arrow functions — a shorter syntax used everywhere in current JavaScript.

• Classic function: function greet(name) { return "Hi " + name; }
• Arrow function: const greet = (name) => `Hi ${name}`;
• === compares value and type — always prefer it over the loose ==.
• Array methods like .map() and .filter() often replace manual loops.

💡 Practical Skill: Reach for .filter() and .map() before a manual for loop — they're shorter, and communicate intent more clearly.

const attendance = [18, 15, 20, 9, 17];const totalClasses = 20; const checkStatus = (classesAttended) => {  const rate = (classesAttended / totalClasses) * 100;  if (rate >= 80) return "Eligible for certificate";  if (rate >= 60) return "Needs make-up session";  return "At risk — contact student";}; attendance.forEach((classes, index) => {  console.log(`Student ${index + 1}: ${checkStatus(classes)}`);});