Remainder Operator (%) in JavaScript
🔍 What is the Remainder Operator?
The % operator in JavaScript is known as the remainder operator (sometimes informally called the modulus operator). It returns the remainder left over when one number is divided by another.
>>“When division doesn't go perfectly, the remainder tells the rest of the story.” 📘
📌 Syntax
Remainder Operator Syntax
result = dividend % divisor;🧠 How It Works
The remainder operator calculates:
a % b → what’s left after dividing a by bIt's different from / which gives you the quotient. For example:
Basic Example
console.log(10 / 3); // 3.333...
console.log(10 % 3); // 1 (because 3 * 3 = 9, remainder = 1)📊 Examples
Various Remainder Examples
console.log(7 % 2); // 1 (7 divided by 2 is 3 with remainder 1)
console.log(10 % 5); // 0 (10 is exactly divisible by 5)
console.log(15 % 4); // 3 (4 * 3 = 12, remainder is 3)
console.log(4 % 10); // 4 (divisor is bigger than dividend)
console.log(-7 % 3); // -1 (sign follows the dividend)Note
⚠️ The sign of the result always follows the dividend (the number on the left).
🎯 Common Use Cases
- 💡 Checking Even or Odd: if (num % 2 === 0) means it's even.
- 🔁 Loop Wrapping: Cycling through values in arrays or counters.
- ⏱ Timed Intervals: Run a function every N iterations.
Even/Odd Checker
const num = 7;
if (num % 2 === 0) {
console.log("Even");
} else {
console.log("Odd"); // Output: "Odd"
}🧪 Difference from Math.floor & Math.trunc
While % gives the remainder, methods like Math.floor() give you the largest whole number less than or equal to the division result.
Math.floor vs %
console.log(Math.floor(7 / 3)); // 2
console.log(7 % 3); // 1📚 Learn More
>>“Sometimes, what’s left is more important than what’s gone.” – Think like a dev. 🔍