Operadores
Este capítulo documenta todos os operadores, expressões e keywords da linguagem JavaScript .
Expressões e operadores por categoria
Para uma lista alfabética ver a barra lateral à esquerda.
Expressões primárias
Palavras-chave e expressões básicas em JavaScript.
this
A palavra-chave
this
refere-se ao contexto de execução da função.function
A palavra-chave
function
define uma função.- Experimental
class
A palavra-chave
class
define uma classe.- Experimental
function*
A palavra-chave
function*
define um gerador de função.- Experimental
yield
Pausa e retorma uma função de gerador
- Experimental
yield*
Delegar a outra função gerador ou objeto iterável.
[]
Array initializer/literal syntax.
{}
Object initializer/literal syntax.
/ab+c/i
Regular expression literal syntax.
- Experimental
[for (x of y) x]
Array comprehensions.
- Experimental
(for (x of y) y)
Generator comprehensions.
( )
Grouping operator.
Left-hand-side expressions
Left values are the destination of an assignment.
- Property accessors
Member operators provide access to a property or method of an object (
object.property
andobject["property"]
).new
The
new
operator creates an instance of a constructor.- Experimental
super
The
super
keyword calls the parent constructor.- Experimental
...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.
Incremento e decremento
Unary operators
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.
Operadores aritméticos
Operadores relacionais
A comparison operator compares its operands and returns a Boolean
value based on whether the comparison is true.
Operadores de igualdade
Bitwise shift operators
Binary bitwise operators
Operadores Lógicos Binários
Operador de Condicional (ternário)
(condition ? ifTrue : ifFalse)
O operador condicional retorna um dos dois valores baseado no valor lógico da condição.
Assignment operators
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.
>>>=
Unsigned right shift assignment.
&=
Bitwise AND assignment.
^=
Bitwise XOR assignment.
|=
Bitwise OR assignment.
- Experimental
{a, b} = {a:1, b:2}
Experimental[a, b] = [1, 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.
Comma operator
,
The comma operator allows multiple expressions to be evaluated in a single statement and returns the result of the last expression.
Non-standard features
- Non-standardLegacy 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 oneyield
expression.- Non-standardExpression closures
The expression closure syntax is a shorthand for writing simple function.