And or xor javascript

Expressions and operators

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

Expressions and operators by category

For an alphabetical listing see the sidebar on the left.

Primary expressions

Basic keywords and general expressions in JavaScript. These expressions have the highest precedence (higher than operators).

The this keyword refers to a special property of an execution context.

Basic null , boolean, number, and string literals.

Array initializer/literal syntax.

Object initializer/literal syntax.

The function keyword defines a function expression.

The class keyword defines a class expression.

The function* keyword defines a generator function expression.

The async function defines an async function expression.

The async function* keywords define an async generator function expression.

Regular expression literal syntax.

Left-hand-side expressions

Left values are the destination of an assignment.

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

The optional chaining operator returns undefined instead of causing an error if a reference is nullish ( null or undefined ).

The new operator creates an instance of a constructor.

In constructors, new.target refers to the constructor that was invoked by new .

An object exposing context-specific metadata to a JavaScript module.

The super keyword calls the parent constructor or allows accessing properties of the parent object.

The import() syntax allows loading a module asynchronously and dynamically into a potentially non-module environment.

Increment and decrement

Postfix/prefix increment and postfix/prefix decrement operators.

Postfix increment operator.

Postfix decrement operator.

Prefix increment operator.

Prefix decrement operator.

Unary operators

A unary operation is an operation with only one operand.

The delete operator deletes a property from an object.

The void operator evaluates an expression and discards its return value.

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.

Pause and resume an async function and wait for the promise’s fulfillment/rejection.

Arithmetic operators

Arithmetic operators take numerical values (either literals or variables) as their operands and return a single numerical value.

Relational operators

A comparison operator compares its operands and returns a boolean value based on whether the comparison is true.

Less than or equal operator.

Greater than or equal operator.

The instanceof operator determines whether an object is an instance of another object.

The in operator determines whether an object has a given property.

Note: => is not an operator, but the notation for Arrow functions.

Equality operators

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

Strict inequality operator.

Bitwise shift operators

Operations to shift all bits of the operand.

Bitwise left shift operator.

Bitwise right shift operator.

Bitwise unsigned right shift operator.

Binary bitwise operators

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

Binary logical operators

Logical operators implement boolean (logical) values and have short-circuiting behavior.

Nullish Coalescing Operator.

Conditional (ternary) operator

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

Assignment operators

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

Unsigned right shift assignment.

Nullish coalescing assignment.

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.

Yield operators

Pause and resume a generator function.

Delegate to another generator function or iterable object.

Spread syntax

Spread syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

Comma operator

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

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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JavaScript Bitwise Operations

JavaScript stores numbers as 64 bits floating point numbers, but all bitwise operations are performed on 32 bits binary numbers.

Before a bitwise operation is performed, JavaScript converts numbers to 32 bits signed integers.

After the bitwise operation is performed, the result is converted back to 64 bits JavaScript numbers.

The examples above uses 4 bits unsigned binary numbers. Because of this ~ 5 returns 10.

Since JavaScript uses 32 bits signed integers, it will not return 10. It will return -6.

11111111111111111111111111111010 (~5 = -6)

A signed integer uses the leftmost bit as the minus sign.

JavaScript Bitwise AND

When a bitwise AND is performed on a pair of bits, it returns 1 if both bits are 1.

JavaScript Bitwise OR

When a bitwise OR is performed on a pair of bits, it returns 1 if one of the bits is 1:

JavaScript Bitwise XOR

When a bitwise XOR is performed on a pair of bits, it returns 1 if the bits are different:

JavaScript Bitwise AND (&)

Bitwise AND returns 1 only if both bits are 1:

Decimal	Binary
5	00000000000000000000000000000101
1	00000000000000000000000000000001
5 & 1	00000000000000000000000000000001 (1)

Example

JavaScript Bitwise OR (|)

Bitwise OR returns 1 if one of the bits is 1:

Decimal	Binary
5	00000000000000000000000000000101
1	00000000000000000000000000000001
5 | 1	00000000000000000000000000000101 (5)

Example

JavaScript Bitwise XOR (^)

Bitwise XOR returns 1 if the bits are different:

Decimal	Binary
5	00000000000000000000000000000101
1	00000000000000000000000000000001
5 ^ 1	00000000000000000000000000000100 (4)

Example

JavaScript Bitwise NOT (~)

Example

JavaScript (Zero Fill) Bitwise Left Shift (<<)

This is a zero fill left shift. One or more zero bits are pushed in from the right, and the leftmost bits fall off:

Decimal	Binary
5	00000000000000000000000000000101
5	00000000000000000000000000001010 (10)

Example

JavaScript (Sign Preserving) Bitwise Right Shift (>>)

This is a sign preserving right shift. Copies of the leftmost bit are pushed in from the left, and the rightmost bits fall off:

Decimal	Binary
-5	11111111111111111111111111111011
-5 >> 1	11111111111111111111111111111101 (-3)

Example

JavaScript (Zero Fill) Right Shift (>>>)

This is a zero fill right shift. One or more zero bits are pushed in from the left, and the rightmost bits fall off:

Decimal	Binary
5	00000000000000000000000000000101
5 >>> 1	00000000000000000000000000000010 (2)

Example

Binary Numbers

Binary numbers with only one bit set are easy to understand:

Binary Representation	Decimal value
00000000000000000000000000000001	1
00000000000000000000000000000010	2
00000000000000000000000000000100	4
00000000000000000000000000001000	8
00000000000000000000000000010000	16
00000000000000000000000000100000	32
00000000000000000000000001000000	64

Setting a few more bits reveals the binary pattern:

Binary Representation	Decimal value
00000000000000000000000000000101	5 (4 + 1)
00000000000000000000000000001101	13 (8 + 4 + 1)
00000000000000000000000000101101	45 (32 + 8 + 4 + 1)

JavaScript binary numbers are stored in two’s complement format.

This means that a negative number is the bitwise NOT of the number plus 1:

Binary Representation	Decimal value
00000000000000000000000000000101	5
11111111111111111111111111111011	-5
00000000000000000000000000000110	6
11111111111111111111111111111010	-6
00000000000000000000000000101000	40
11111111111111111111111111011000	-40

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