Javascript Operators

Operators used in Javascript

Below is a listing of often used operators in javascript to help understand some of the used code in Oolite scripts. A quick introduction and further links can be found in Scripting Oolite with JavaScript.

Artithmetic Operators

Operator Description

+	Addition 

-	Subtraction 

*	Multiplication 

/	Division 

%	Modulus (remainder of a division) 

++	Increment (++X means increment by one X before use and X++ means increment X after use

--	Decrement (--X means idecrement by one X before use and X-- means decrement X after use

Assignment Operators

Operator Description

=	Assign 

+=	Add and assign. For example, x+=y is the same as x=x+y. 

-=	Subtract and assign. For example, x-=y is the same as x=x-y. 

*=	Multiply and assign. For example, x*=y is the same as x=x*y. 

/=	Divide and assign. For example, x/=y is the same as x=x/y. 

%=	Modulus and assign. For example, x%=y is the same as x=x%y. 

Comparison Operators

Operator Description

==	Is equal to 

===	Is identical (is equal to and is of the same type) 

!=	Is not equal to 

!==	Is not identical 

>	Greater than 

>=	Greater than or equal to 

<	Less than 

<=	Less than or equal to 

Logical/boolean Operators

Operator Description

&&	and 

||	or 

!	not 

String Operators

In JavaScript, a string is simply a piece of text.

Operator Description

=	Assignment 

+	Concatenate (join two strings together) 

+=	Concatenate and assign

Bit Operators

Operator Description

&	Bitwise and

|	Bitwise or

^	Bitwise exclusive or (xor)

~	Flip all bits (invert 0 to 1 and 1 to 0)

Bitshifting operation converts to 32-bit integers, big-endian order and returns a result of the same type as the left operand.

<<	Shift bits to the left (9 << 2 yields 36)

>>	Shift bits to the right, keep sign (9 >> 2 yields 2 BUT -9 >> 2 yields -3)

>>>	Shift bits to the right, discard sign bit (9 >>> 2 yields 2 BUT -9 >>> 2 yields 1073741821)