Javascript Operators

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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)