JavaScript Operators

29 in total

Operators do the actual work in an expression — comparing values, combining them, checking types. This includes everyday symbols like === and the ones that trip people up: optional chaining (?.), nullish coalescing (??) and the spread syntax (...). Browse all 29 below, each with a clear explanation and live examples.

Name	Description
+	Adds numbers — but also concatenates strings, which causes the classic type-coercion gotchas.
=>	A short syntax for writing functions that also inherits this from the surrounding scope.
=	Assigns a value to a variable. Not to be confused with == or === (comparison).
delete	Removes a property from an object. Not for deleting variables or array elements cleanly.
destructuring	Unpacks values from arrays or properties from objects into distinct variables in one step.
/	Divides one number by another. Dividing by zero gives Infinity, not an error.
**	Raises the left operand to the power of the right. A concise alternative to Math.pow().
>	Tests whether the left value is greater than the right. Works on numbers and, alphabetically, strings.
>=	Tests whether the left value is greater than or equal to the right.
in	Tests whether a property (or array index) exists in an object, returning true or false.
!=	Tests whether two values are not equal, after type coercion. Prefer !== instead.
instanceof	Tests whether an object was created from a particular constructor or class.
<	Tests whether the left value is less than the right. Numeric for numbers, alphabetical for strings.
<=	Tests whether the left value is less than or equal to the right.
&&	Returns the first falsy value or the last value. Short-circuits, and is used for conditional execution.
!	Inverts a boolean. The double form (!!) converts any value to a real true/false.
\|\|	Returns the first truthy value or the last value. Short-circuits, and was the classic default-value operator.
==	Compares two values for equality after converting their types. Prefer === to avoid surprises.
*	Multiplies two numbers, coercing string operands to numbers.
new	Creates an instance of a class or constructor function, running its constructor.
??	Returns the right-hand value only when the left is null or undefined — a safer default than \|\|.
?.	Safely accesses nested properties, returning undefined instead of throwing if something is missing.
%	Returns the remainder after dividing one number by another. Used for even/odd and wrapping.
...	Expands an array, object or iterable into individual elements. Also used for rest parameters.
===	Compares two values for equality without type conversion. The equality check you should use.
!==	Tests whether two values are not equal, without type coercion. The not-equal you should use.
-	Subtracts one number from another, and as a unary operator negates or converts to a number.
?:	A compact one-line if...else that chooses between two values based on a condition.
typeof	Returns a string naming the type of a value, such as "string", "number" or "object".

References