在Java中用小括号括起来后，换行符有什么危险? [英] When is it dangerous to line break after a close parenthesis in Javascript?

问题描述

• 在圆括号内将长代码行破坏的危险是什么?

• What are the dangers of breaking a line of long code up at a close parenthesis?

何时可以使用Javascript自动插入分号(大概是危险的吧?).

When could a semicolon be automatically inserted by Javascript (presumably that is the danger, right?).

为什么使用)作为JSLint所皱眉"的换行器?

Why is using a ) as a line breaker "frowned upon" by JSLint?

在Javascript中，有时我会在)处看到一长行代码，像这样( 示例 ):

In Javascript I sometimes see one long line of code broken up at a ) like this (example):

function ()
{

或这样( 示例 ):

or like this (example):

object.methodOne()
      .methodTwo();

但是当阅读 对jsLint的换行期望 时，它说:

But when reading the line break expectations for jsLint, it says:

作为对分号插入机制的进一步防御，JSLint希望仅在以下标点字符或运算符之一之后才中断长语句:

As a further defense against the semicolon insertion mechanism, JSLint expects long statements to be broken only after one of these punctuation characters or operators:

, ; : { } ( [ = < > ? ! + - * / % ~ ^ | &
== != <= >= += -= *= /= %= ^= |= &= << >> || &&
=== !== <<= >>= >>> >>>=

JSLint不会期望在标识符，字符串，数字，更小数或后缀运算符之后出现长语句中断:

JSLint does not expect to see a long statement broken after an identifier, a string, a number, closer, or a suffix operator:

. ) ] ++ --

因此，圆括号被选为JSLint不希望看到的"换行符.

So the close parenthesis is singled out as a line breaker that JSLint "doesn't expect to see."

我更愿意使用

function() 
{

因为我发现它更具可读性，并且已经在其他语言中使用它，但是目前我使用:

since I find it more readable, and I already use it in other languages, but currently I use:

function () {

我可以安全地使用)断开长行吗?

Could I safely use the ) to break up long lines?

推荐答案

此链接应对此进行全部解释:

This link should explain it all:

JavaScript分号插入

危险"伴随着(摘自上面的链接，重点已添加):

The "danger" is with (taken from the above link, emphasis added):

语法中有五种限制形式，它们是后缀运算符 ++和-， continue 语句， break 语句， return 语句和 throw 语句.

There are five restricted productions in the grammar, they are the postfix operators ++ and --, continue statements, break statements, return statements, and throw statements.

function()不在该危险"列表中.但是，在编写分号自由代码时(我不确定这是否是您的目标:-)，应该防止以字符开头的行(例如(或[)可能会以或继续一个表达式.以下代码显示了可能错误的代码示例:

function() is not in that "danger" list. However, when writing semi-colon free-code (I'm not sure if this is your aim :-), one should guard against lines starting with characters -- such as ( or [ -- that may start or continue an expression. The following code shows an example of code which is likely wrong:

x()
(function (){...})()

如您所见，使用)作为换行符可以使表达式能够巧妙地继续 ，而无需在下一行使用明确的分号 iff 可以继续表达.我将程序编写为(如果确实是以下意图):

As you can see, using ) as a line-breaker may make the expression able to continue on subtly without an explicit semi-colon iff the next line can continue the expression. I write the proceeding as (if the following is indeed the intent):

x()
;(function (){...})()

我个人不喜欢JSLint :-) 编码愉快.

Personally, I dislike JSLint :-) Happy coding.

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