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JavaScript Comparisons & Booleans

What are Arithmetic Operators?

Arithmetic operators are used to perform mathematical calculations like addition, subtraction, and multiplication. They are the most basic building blocks of programming logic.

Operator Operation Description
+ Addition Adds two values together
- Subtraction Subtracts the right value from the left value
* Multiplication Multiplies two values
/ Division Divides the left value by the right value
% Modulus Returns the remainder after division

Note: While the basic behavior is the same across languages, how they handle things like "Integer Division" (e.g., 5 / 2) can vary.

Comparison Operators

Operator Description
== equal to (value only)
=== equal value and equal type
!= not equal
!== not equal value or not equal type
> greater than
< less than
>= greater than or equal to
<= less than or equal to
? ternary operator

Strict Equality (===)

In JavaScript, == converts variable values to the same type before comparing. This is called Type Coercion. === does not convert type.

let x = 5;
x == "5";  // true (string "5" converted to number 5)
x === "5"; // false (number vs string)

Logical Operators

  • &&: logical and
  • ||: logical or
  • !: logical not

Conditional (Ternary) Operator

JavaSript also contains a conditional operator that assigns a value to a variable based on some condition.

Syntax: variablename = (condition) ? value1:value2

let voteable = (age < 18) ? "Too young":"Old enough";

Always use Strict Equality

To avoid bugs, always use === and !== instead of == and !=. It makes your code more predictable.