Operatory

This chapter documents all the JavaScript language operators, expressions and keywords.

Podstawowe słowa kluczowe i wyrażenia w  JavaScript.

this

Słowo this odnosi się do kontekstu wywołania.

function

Słowo function umożliwia zdefniowanie wyrażenia funkcji .

class

Słowo class definiuje wyrażenie klasy.

function*

The function* keyword defines a generator function expression.

yield

Pause and resume a generator function

yield*

Delegate to another generator function or iterable object.

[]

Array initializer/literal syntax.

{}

Object initializer/literal syntax.

/ab+c/i

Regular expression literal syntax.

[for (x of y) x]

Array comprehensions.

(for (x of y) y)

Generator comprehensions.

( )

Grouping operator.

Left values are the destination of an assignment.

Property accessors

Member operators provide access to a property or method of an object
(object.property and object["property"]).

new

The new operator creates an instance of a constructor.

super

The super keyword calls the parent constructor.

...obj

The spread operator allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) are expected.

Postfix/prefix increment and postfix/prefix decrement operators.

A++

Postfix increment operator.

A--

Postfix decrement operator.

++A

Prefix increment operator.

--A

Prefix decrement operator.

A unary operation is operation with only one operand.

delete

The delete operator deletes a property from an object.

void

The void operator discards an expression's return value.

typeof

The typeof operator determines the type of a given object.

+

The unary plus operator converts its operand to Number type.

-

The unary negation operator converts its operand to Number type and then negates it.

~

Bitwise NOT operator.

!

Logical NOT operator.

+

Addition operator.

-

Subtraction operator.

/

Division operator.

*

Multiplication operator.

%

Remainder operator.

Operator porównania, jak nazwa wskazuje, porównuje operandy  i zwraca wartość logiczną zależną od tego, czy wartość porównania jest prawdziwa. 

in

Operator in ustala, czy obiekt posiada daną właściwość.

instanceof

Operator instanceof ustala czy obiekt jest instancją innego obiektu.

<

Less than operator.

>

Greater than operator.

<=

Less than or equal operator.

>=

Greater than or equal operator.

The result of evaluating an equality operator is always of type Boolean based on whether the comparison is true.

==

Equality operator.

!=

Inequality operator.

===

Identity operator.

!==

Nonidentity operator.

Operations to shift all bits of the operand.

<<

Bitwise left shift operator.

>>

Bitwise right shift operator.

>>>

Bitwise unsigned right shift operator.

Bitwise operators treat their operands as a set of 32 bits (zeros and ones) and return standard JavaScript numerical values.

&

Bitwise AND.

|

Bitwise OR.

^

Bitwise XOR.

Logical operators are typically used with boolean (logical) values, and when they are, they return a boolean value.

&&

Logical AND.

||

Logical OR.

(condition ? ifTrue : ifFalse)

The conditional operator returns one of two values based on the logical value of the condition.

An assignment operator assigns a value to its left operand based on the value of its right operand.

=

Assignment operator.

*=

Multiplication assignment.

/=

Division assignment.

%=

Remainder assignment.

+=

Addition assignment.

-=

Subtraction assignment

<<=

Left shift assignment.

>>=

Right shift assignment.

>>>= (en-US)

Unsigned right shift assignment.

&=

Bitwise AND assignment.

^=

Bitwise XOR assignment.

|=

Bitwise OR assignment.

[a, b] = [1, 2]
{a, b} = {a:1, b:2}

Destructuring assignment allows you to assign the properties of an array or object to variables using syntax that looks similar to array or object literals.

,

The comma operator allows multiple expressions to be evaluated in a single statement and returns the result of the last expression.

Legacy generator function

The function keyword can be used to define a legacy generator function inside an expression. To make the function a legacy generator, the function body should contains at least one yield expression.

Expression closures

The expression closure syntax is a shorthand for writing simple function.

• Operator precedence