JavaScript Operators: The Basics You Need to Know

1. What are Operators?

If variables are the "nouns" of our code (the things), operators are the "verbs" (the actions). They take one or more values and produce a result.

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2. Arithmetic Operators: The Math Basics

These are the ones you already know from school. We use them for everything from calculating the total in a shopping cart to determining the position of an element on a screen.

• Addition (+)

• Subtraction (-)

• Multiplication (*)

• Division (/)

• Remainder (%): This gives you what is left over after a division.

Real-World Example:

JavaScript

let pricePerItem = 500;
let quantity = 3;
let shippingFee = 50;

let subtotal = pricePerItem * quantity; // 1500
let totalBill = subtotal + shippingFee; // 1550

// Check if a number is even using Remainder
let isEven = (totalBill % 2 === 0); 

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3. Comparison Operators: Making Decisions

Comparison operators are the backbone of logic. They look at two values and return either true or false.

The "Double Equals" vs. "Triple Equals"

This is the most common mistake for beginners.

• == (Abstract Equality): It checks the value but ignores the data type. It tries to force the values to be the same type before comparing.

• === (Strict Equality): It checks both the value and the data type.

Console Example:

JavaScript

console.log(5 == "5");  // true (Value is same, type is ignored)
console.log(5 === "5"); // false (Value is same, but Number is not String)

Pro-tip: In the Web Dev Cohort 2026, we always aim for === to avoid hidden bugs.

Other Comparisons:

• != (Not equal)

• > (Greater than)

• < (Less than)

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4. Logical Operators: The Gatekeepers

Logical operators allow us to combine multiple conditions. This is how we handle complex scenarios, like checking if a user is both logged in and has a premium subscription.

• && (AND): True only if both sides are true.

• || (OR): True if at least one side is true.

• ! (NOT): Reverses the value (true becomes false).

Example:

JavaScript

let isLoggedIn = true;
let hasSubscription = false;

// Can they watch the movie?
let canWatch = isLoggedIn && hasSubscription; // false

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5. Assignment Operators: The Shorthand

We use these to assign values to variables. You already know =, but there are "shortcut" versions that make your code much cleaner.

• =: Basic assignment.

• +=: Add and assign. (x += 5 is the same as x = x + 5)

• -=: Subtract and assign.

Example:

JavaScript

let score = 10;
score += 5; // score is now 15
score -= 2; // score is now 13

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Final Quest: The Operator Challenge

To finish this assignment, let's run a small script that combines all these concepts.

Assignment Implementation

JavaScript

// 1. Arithmetic Operations
let num1 = 20;
let num2 = 10;
console.log("Sum:", num1 + num2);
console.log("Remainder:", num1 % 3);

// 2. Comparison (== vs ===)
let a = 10;
let b = "10";
console.log("Loose Comparison:", a == b);  // true
console.log("Strict Comparison:", a === b); // false

// 3. Logical Conditions
let temperature = 35;
let isSunny = true;

if (temperature > 30 && isSunny) {
  console.log("It is a hot sunny day.");
}

// 4. Assignment Shorthand
let wallet = 1000;
wallet -= 200; // Spent 200 on lunch
console.log("Remaining Balance:", wallet);

By mastering these operators, you have gained the tools to make your code dynamic. Instead of just storing data, you are now manipulating it.