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• 表达式和运算符 (按类别)
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

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

表达式和运算符 (按类别)

对于按字母顺序清单，请参阅左侧边栏。

首要表达式

JavaScript 中的基本关键字和通用表达式。

this

this 关键字引用执行上下文特殊特性。

function

function 关键字定义函数表达式。

class

class 关键字定义类表达式。

function*

function* keyword defines a generator function expression.

yield

Pause and resume a generator function.

yield*

Delegate to another generator function or iterable object.

async function

async function defines an async function expression.

await

Pause and resume an async function and wait for the promise's resolution/rejection.

[]

Array initializer/literal syntax.

{}

Object initializer/literal syntax.

/ab+c/i

Regular expression literal syntax.

( )

Grouping operator.

左手侧表达式

Left values are the destination of an assignment.

特性访问器

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

new

new operator creates an instance of a constructor.

new.target

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

super

super keyword calls the parent constructor.

...obj

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

递增和递减

Postfix/prefix increment and postfix/prefix decrement operators.

A++

后缀递增运算符。

A--

后缀递减运算符。

++A

前缀递增运算符。

--A

前缀递减运算符。

一元运算符

A unary operation is operation with only one operand.

delete

delete operator deletes a property from an object.

void

void 运算符丢弃表达式的返回值。

typeof

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.

~

按位 NOT 运算符。

!

逻辑 NOT 运算符。

算术运算符

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

+

Addition operator.

-

Subtraction operator.

/

Division operator.

*

Multiplication operator.

%

Remainder operator.

**

Exponentiation operator.

关系运算符

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

in

in operator determines whether an object has a given property.

instanceof

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

<

小于运算符。

>

Greater than operator.

<=

Less than or equal operator.

>=

Greater than or equal operator.

Note: => is not an operator, but the notation for 箭头函数 .

相等运算符

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

==

相等运算符。

!=

Inequality operator.

===

Identity operator.

!==

Nonidentity operator.

按位移位运算符

Operations to shift all bits of the operand.

<<

Bitwise left shift operator.

>>

Bitwise right shift operator.

>>>

Bitwise unsigned right shift operator.

二进制按位运算符

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

&

按位 AND。

|

按位 OR。

^

按位 XOR。

二进制逻辑运算符

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

&&

逻辑 AND。

||

逻辑 OR。

条件 (三元) 运算符

(condition ? ifTrue : ifFalse)

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

赋值运算符

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.

&&=

Logical AND assignment.

||=

Logical OR assignment.

??=

Logical nullish 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.

逗号运算符

,

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

规范

规范
ECMAScript (ECMA-262) 在该规范中的 ECMAScript Language: Expressions 定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
Addition ( + )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Addition assignment ( x += y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Assignment ( x = y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
async function expression	Chrome 55	Edge 15	Firefox 52	IE No	Opera 42	Safari 10.1	WebView Android 55	Chrome Android 55	Firefox Android 52	Opera Android 42	Safari iOS 10.3	Samsung Internet Android 6.0	nodejs 7.6.0 7.6.0 7.0.0 Disabled Disabled From version 7.0.0: this feature is behind the --harmony runtime flag.
await	Chrome 55	Edge 14	Firefox 52	IE No	Opera 42	Safari 10.1	WebView Android 55	Chrome Android 55	Firefox Android 52	Opera Android 42	Safari iOS 10.3	Samsung Internet Android 6.0	nodejs 7.6.0 7.6.0 7.0.0 Disabled Disabled From version 7.0.0: this feature is behind the --harmony runtime flag.
Bitwise AND ( a & b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise AND assignment ( x &= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise NOT ( ~a )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise OR ( a | b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise OR assignment ( x |= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise XOR ( a ^ b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise XOR assignment ( x ^= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
class	Chrome 42	Edge 13	Firefox 45	IE No	Opera 29	Safari 7	WebView Android 42	Chrome Android 42	Firefox Android 45	Opera Android 29	Safari iOS 7	Samsung Internet Android 4.0	nodejs 6.0.0 6.0.0 5.0.0 Disabled Disabled From version 5.0.0: this feature is behind the --harmony runtime flag.
逗号运算符	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Conditional operator ( c ? t : f )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Decrement ( -- )	Chrome 2	Edge 12	Firefox 1	IE 3	Opera 3	Safari 4	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 3.2	Samsung Internet Android 1.0	nodejs 0.1.100
delete	Chrome 1	Edge 12	Firefox 1	IE 4	Opera 9	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Destructuring assignment	Chrome 49	Edge 14	Firefox 41 41 Firefox provided a non-standard destructuring implementation from Firefox 2 to 40.	IE No	Opera 36	Safari 8	WebView Android 49	Chrome Android 49	Firefox Android 41 41 Firefox provided a non-standard destructuring implementation from Firefox 2 to 40.	Opera Android 36	Safari iOS 8	Samsung Internet Android 5.0	nodejs 6.0.0
Division ( / )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Division assignment ( x /= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Equality ( a == b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Exponentiation ( ** )	Chrome 52	Edge 14	Firefox 52	IE No	Opera 39	Safari 10.1	WebView Android 51	Chrome Android 52	Firefox Android 52	Opera Android 41	Safari iOS 10.3	Samsung Internet Android 6.0	nodejs 7.0.0 7.0.0 6.5.0 Disabled Disabled From version 6.5.0: this feature is behind the --harmony runtime flag.
Exponentiation assignment ( x **= y )	Chrome 52	Edge 14	Firefox 52	IE No	Opera 39	Safari 10.1	WebView Android 51	Chrome Android 52	Firefox Android 52	Opera Android 41	Safari iOS 10.3	Samsung Internet Android 6.0	nodejs 7.0.0 7.0.0 6.5.0 Disabled Disabled From version 6.5.0: this feature is behind the --harmony runtime flag.
function	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
function*	Chrome 49	Edge 12	Firefox 26	IE No	Opera 36	Safari 10	WebView Android 49	Chrome Android 49	Firefox Android 26	Opera Android 36	Safari iOS 10	Samsung Internet Android 5.0	nodejs 4.0.0
Greater than ( a > b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Greater than or equal ( a >= b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Grouping operator ()	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
in	Chrome 1	Edge 12	Firefox 1	IE 5.5	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Increment ( ++ )	Chrome 2	Edge 12	Firefox 1	IE 3	Opera 3	Safari 4	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 3.2	Samsung Internet Android 1.0	nodejs 0.1.100
Inequality ( a != b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
instanceof	Chrome 1	Edge 12	Firefox 1	IE 5	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise left shift ( a << b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Left shift assignment ( x <<= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Less than ( a < b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Less than or equal ( a <= b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Logical AND ( && )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Logical AND assignment ( x &&= y )	Chrome 85	Edge 85	Firefox 79	IE No	Opera No	Safari 14	WebView Android 85	Chrome Android 85	Firefox Android No	Opera Android No	Safari iOS 14	Samsung Internet Android No	nodejs No
Logical NOT ( ! )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Logical nullish assignment ( x ??= y )	Chrome 85	Edge 85	Firefox 79	IE No	Opera No	Safari 14	WebView Android 85	Chrome Android 85	Firefox Android No	Opera Android No	Safari iOS 14	Samsung Internet Android No	nodejs No
Logical OR ( || )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Logical OR assignment ( x ||= y )	Chrome 85	Edge 85	Firefox 79	IE No	Opera No	Safari 14	WebView Android 85	Chrome Android 85	Firefox Android No	Opera Android No	Safari iOS 14	Samsung Internet Android No	nodejs No
Multiplication ( * )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Multiplication assignment ( x *= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
new	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
new.target	Chrome 46	Edge 13	Firefox 41	IE No	Opera 33	Safari 11	WebView Android 46	Chrome Android 46	Firefox Android 41	Opera Android 33	Safari iOS 11	Samsung Internet Android 5.0	nodejs 5.0.0
Nullish coalescing operator ( ?? )	Chrome 80	Edge 80	Firefox 72	IE No	Opera 67	Safari 13.1	WebView Android 80	Chrome Android 80	Firefox Android No	Opera Android No	Safari iOS 13.4	Samsung Internet Android No	nodejs 14.0.0
对象初始化器	Chrome 1	Edge 12	Firefox 1	IE 1	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Optional chaining operator ( ?. )	Chrome 80 80 79 Disabled Disabled ). To change preferences in Chrome, visit	Edge 80 80 79 Disabled Disabled From version 79: this feature is behind the Experimental JavaScript preference (needs to be set to true ).	Firefox 74	IE No	Opera 67 67 66 Disabled Disabled From version 66: this feature is behind the Experimental JavaScript preference (needs to be set to true ).	Safari 13.1	WebView Android 80	Chrome Android 80 80 79 Disabled Disabled ). To change preferences in Chrome, visit	Firefox Android No	Opera Android No	Safari iOS 13.4	Samsung Internet Android No	nodejs 14.0.0
Pipeline operator ( |> )	Chrome No	Edge No	Firefox No	IE No	Opera No	Safari No	WebView Android No	Chrome Android No	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android No	nodejs No
特性访问器	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Remainder ( % )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Remainder assignment ( x %= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise right shift ( a >> b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Right shift assignment ( x >>= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Strict equality ( a === b )	Chrome 1	Edge 12	Firefox 1	IE 4	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Strict inequality ( a !== b )	Chrome 1	Edge 12	Firefox 1	IE 4	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Subtraction ( - )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Subtraction assignment ( x -= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
super	Chrome 42	Edge 13	Firefox 45	IE No	Opera 29	Safari 7	WebView Android 42	Chrome Android 42	Firefox Android 45	Opera Android 29	Safari iOS 7	Samsung Internet Android 4.0	nodejs 6.0.0
this	Chrome 1	Edge 12	Firefox 1	IE 4	Opera 9.5	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
typeof	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Unary negation ( - )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Unary plus ( + )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 4	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Bitwise unsigned right shift ( a >>> b )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
Unsigned right shift assignment ( x >>>= y )	Chrome 1	Edge 12	Firefox 1	IE 3	Opera 3	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs 0.1.100
void	Chrome 1	Edge 12	Firefox 1	IE 5	Opera 4	Safari 3.2	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 3	Samsung Internet Android 1.0	nodejs 0.1.100
yield	Chrome 39	Edge 12	Firefox 26 26 Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification. Starting with Firefox 29, an IteratorResult object returned for completed generator function.	IE No	Opera 26	Safari 10	WebView Android 39	Chrome Android 39	Firefox Android 26 26 Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification. Starting with Firefox 29, an IteratorResult object returned for completed generator function.	Opera Android 26	Safari iOS 10	Samsung Internet Android 4.0	nodejs 4.0.0 4.0.0 0.12 Disabled Disabled From version 0.12: this feature is behind the --harmony runtime flag.
yield*	Chrome 39	Edge 12	Firefox 27 27 Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.	IE No	Opera 26	Safari 10	WebView Android 39	Chrome Android 39	Firefox Android 27 27 Starting with Firefox 33, the parsing of the yield expression has been updated to conform with the ES2015 specification.	Opera Android 26	Safari iOS 10	Samsung Internet Android 4.0	nodejs 4.0.0 4.0.0 0.12 Disabled Disabled From version 0.12: this feature is behind the --harmony runtime flag.

图例

完整支持

完整支持

不支持

不支持

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

见实现注意事项。

用户必须明确启用此特征。

用户必须明确启用此特征。

另请参阅

• 运算符优先级

元数据

• 最后修改： Jul 9, 2020

相关话题

1. JavaScript
2. 教程：
3. 完全初学者

   1. JavaScript 基础
   2. JavaScript 第一步
   3. JavaScript 构建块
   4. 引入 JavaScript 对象
4. JavaScript 指南

   1. 介绍
   2. 语法和类型
   3. 控制流程和错误处理
   4. 循环和迭代
   5. 函数
   6. 表达式和运算符
   7. 数字和日期
   8. 文本格式化
   9. 正则表达式
   10. 索引集合
   11. 键控集合
   12. Working with objects
   13. 对象模型的细节
   14. Using promises
   15. 迭代器和生成器
   16. Meta programming
   17. JavaScript 模块
5. 中间体

   1. Client-side JavaScript frameworks
   2. 客户端侧 Web API
   3. 重新介绍 JavaScript
   4. JavaScript 数据结构
   5. 相等比较和相同
   6. 闭包
6. 高级

   1. 继承和原型链
   2. 严格模式
   3. JavaScript 类型数组
   4. 内存管理
   5. 并发模型和事件循环
7. 参考：
8. 内置对象

   1. AggregateError
   2. Array
   3. ArrayBuffer
   4. AsyncFunction
   5. Atomics
   6. BigInt
   7. BigInt64Array
   8. BigUint64Array
   9. 布尔
   10. DataView
   11. Date
   12. Error
   13. EvalError
   14. FinalizationRegistry
   15. Float32Array
   16. Float64Array
   17. Function
   18. Generator
   19. GeneratorFunction
   20. Infinity
   21. Int16Array
   22. Int32Array
   23. Int8Array
   24. InternalError
   25. Intl
   26. JSON
   27. Map
   28. Math
   29. NaN
   30. Number
   31. Object
   32. Promise
   33. Proxy
   34. RangeError
   35. ReferenceError
   36. Reflect
   37. RegExp
   38. Set
   39. SharedArrayBuffer
   40. String
   41. Symbol
   42. SyntaxError
   43. TypeError
   44. TypedArray
   45. URIError
   46. Uint16Array
   47. Uint32Array
   48. Uint8Array
   49. Uint8ClampedArray
   50. WeakMap
   51. WeakRef
   52. WeakSet
   53. WebAssembly
   54. decodeURI()
   55. decodeURIComponent()
   56. encodeURI()
   57. encodeURIComponent()
   58. escape()
   59. eval()
   60. globalThis
   61. isFinite()
   62. isNaN()
   63. null
   64. parseFloat()
   65. parseInt()
   66. undefined
   67. unescape()
   68. uneval()
9. 表达式 & 运算符

   1. Addition (+)
   2. Addition assignment (+=)
   3. Assignment (=)
   4. Bitwise AND (&)
   5. Bitwise AND assignment (&=)
   6. Bitwise NOT (~)
   7. Bitwise OR (|)
   8. Bitwise OR assignment (|=)
   9. Bitwise XOR (^)
   10. Bitwise XOR assignment (^=)
   11. Comma operator (,)
   12. 条件 (三元) 运算符
   13. Decrement (--)
   14. Destructuring assignment
   15. Division (/)
   16. Division assignment (/=)
   17. Equality (==)
   18. Exponentiation (**)
   19. Exponentiation assignment (**=)
   20. 函数表达式
   21. Greater than (>)
   22. Greater than or equal (>=)
   23. Grouping operator ( )
   24. Increment (++)
   25. Inequality (!=)
   26. Left shift (<<)
   27. Left shift assignment (<<=)
   28. Less than (<)
   29. Less than or equal (<=)
   30. Logical AND (&&)
   31. Logical AND assignment (&&=)
   32. Logical NOT (!)
   33. Logical OR (||)
   34. Logical OR assignment (||=)
   35. Logical nullish assignment (??=)
   36. Multiplication (*)
   37. Multiplication assignment (*=)
   38. Nullish coalescing operator (??)
   39. 对象初始化器
   40. 运算符优先级
   41. Optional chaining (?.)
   42. Pipeline operator (|>)
   43. 特性访问器
   44. Remainder (%)
   45. Remainder assignment (%=)
   46. Right shift (>>)
   47. Right shift assignment (>>=)
   48. Spread syntax (...)
   49. Strict equality (===)
   50. Strict inequality (!==)
   51. Subtraction (-)
   52. Subtraction assignment (-=)
   53. Unary negation (-)
   54. Unary plus (+)
   55. Unsigned right shift (>>>)
   56. Unsigned right shift assignment (>>>=)
   57. 异步函数表达式
   58. await
   59. class expression
   60. delete operator
   61. function* 表达式
   62. in operator
   63. instanceof
   64. new operator
   65. new.target
   66. super
   67. this
   68. typeof
   69. void 运算符
   70. yield
   71. yield*
10. 语句 & 声明

    1. async function
    2. block
    3. break
    4. class
    5. const
    6. continue
    7. debugger
    8. do...while
    9. empty
    10. export
    11. for
    12. for await...of
    13. for...in
    14. for...of
    15. 函数声明
    16. function*
    17. if...else
    18. import
    19. import.meta
    20. label
    21. let
    22. return
    23. switch
    24. throw
    25. try...catch
    26. var
    27. while
    28. with
11. 函数

    1. 箭头函数表达式
    2. 默认参数
    3. 方法定义
    4. 其余参数
    5. 自变量对象
    6. getter
    7. setter
12. 类

    1. Private class fields
    2. Public class fields
    3. 构造函数
    4. extends
    5. static
13. 错误

    1. Error: Permission denied to access property "x"
    2. InternalError: too much recursion
    3. RangeError: argument is not a valid code point
    4. RangeError: invalid array length
    5. RangeError: invalid date
    6. RangeError: precision is out of range
    7. RangeError: radix must be an integer
    8. RangeError: repeat count must be less than infinity
    9. RangeError: repeat count must be non-negative
    10. ReferenceError: "x" is not defined
    11. ReferenceError: assignment to undeclared variable "x"
    12. ReferenceError: can't access lexical declaration`X' before initialization
    13. ReferenceError: deprecated caller or arguments usage
    14. ReferenceError: invalid assignment left-hand side
    15. ReferenceError: reference to undefined property "x"
    16. SyntaxError: "0"-prefixed octal literals and octal escape seq. are deprecated
    17. SyntaxError: "use strict" not allowed in function with non-simple parameters
    18. SyntaxError: "x" is a reserved identifier
    19. SyntaxError: JSON.parse: bad parsing
    20. SyntaxError: Malformed formal parameter
    21. SyntaxError: Unexpected token
    22. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
    23. SyntaxError: a declaration in the head of a for-of loop can't have an initializer
    24. SyntaxError: applying the 'delete' operator to an unqualified name is deprecated
    25. SyntaxError: for-in loop head declarations may not have initializers
    26. SyntaxError: function statement requires a name
    27. SyntaxError: identifier starts immediately after numeric literal
    28. SyntaxError: illegal character
    29. SyntaxError: invalid regular expression flag "x"
    30. SyntaxError: missing ) after argument list
    31. SyntaxError: missing ) after condition
    32. SyntaxError: missing : after property id
    33. SyntaxError: missing ; before statement
    34. SyntaxError: missing = in const declaration
    35. SyntaxError: missing ] after element list
    36. SyntaxError: missing formal parameter
    37. SyntaxError: missing name after . operator
    38. SyntaxError: missing variable name
    39. SyntaxError: missing } after function body
    40. SyntaxError: missing } after property list
    41. SyntaxError: redeclaration of formal parameter "x"
    42. SyntaxError: return not in function
    43. SyntaxError: test for equality (==) mistyped as assignment (=)?
    44. SyntaxError: unterminated string literal
    45. TypeError: "x" has no properties
    46. TypeError: "x" is (not) "y"
    47. TypeError: "x" is not a constructor
    48. TypeError: "x" is not a function
    49. TypeError: "x" is not a non-null object
    50. TypeError: "x" is read-only
    51. TypeError: 'x' is not iterable
    52. TypeError: More arguments needed
    53. TypeError: Reduce of empty array with no initial value
    54. TypeError: X.prototype.y called on incompatible type
    55. TypeError: can't access dead object
    56. TypeError: can't access property "x" of "y"
    57. TypeError: can't assign to property "x" on "y": not an object
    58. TypeError: can't define property "x": "obj" is not extensible
    59. TypeError: can't delete non-configurable array element
    60. TypeError: can't redefine non-configurable property "x"
    61. TypeError: cannot use 'in' operator to search for 'x' in 'y'
    62. TypeError: cyclic object value
    63. TypeError: invalid 'instanceof' operand 'x'
    64. TypeError: invalid Array.prototype.sort argument
    65. TypeError: invalid arguments
    66. TypeError: invalid assignment to const "x"
    67. TypeError: property "x" is non-configurable and can't be deleted
    68. TypeError: setting getter-only property "x"
    69. TypeError: variable "x" redeclares argument
    70. URIError: malformed URI sequence
    71. Warning: -file- is being assigned a //# sourceMappingURL, but already has one
    72. Warning: 08/09 is not a legal ECMA-262 octal constant
    73. Warning: Date.prototype.toLocaleFormat is deprecated
    74. Warning: JavaScript 1.6's for-each-in loops are deprecated
    75. Warning: String.x is deprecated; use String.prototype.x instead
    76. Warning: expression closures are deprecated
    77. Warning: unreachable code after return statement
14. 杂项

    1. JavaScript 技术概述
    2. 词法语法
    3. JavaScript 数据结构
    4. Enumerability and ownership of properties
    5. Iteration protocols
    6. 严格模式
    7. 过渡到严格模式
    8. 模板文字
    9. 弃用特征