为什么这个正则表达式替换不适用于JavaScript，而只适用于其他引擎？ [英] Why does this regex replacement not work for JavaScript, but instead only work for other engines?

问题描述

我想构建一个JavaScript函数，将文本转换为另一种格式，由此：

I want to build a JavaScript function that transforms text into another format, from this:

MATCH 1
1.  [4-17]  `public direct`
2.  [18-29] `routing.key`
MATCH 2
1.  [35-41] `direct`
2.  [42-52] `routingkey`

对此：

MATCH 1: [Group 1: public direct] [Group 2: routing.key]
MATCH 2: [Group 1: direct] [Group 2: routingkey]

我一直在使用正则表达式替换在我的Chrome浏览器控制台中弄乱这段代码，但它不会取代任何东西。这是我尝试过的方法之一， a 是测试对象，问题在于第二次更换：

I've been messing with this code in my Chrome browser console using regex replacements, however it will not replace anything. Here is one of the approaches I've tried, a is the test object, the problem is on the second replacement:

a = "MATCH 1 \n\
1.  [4-17]  `public direct` \n\
2.  [18-29] `routing.key` \n\
MATCH 2 \n\
1.  [35-41] `direct` \n\
2.  [42-52] `routingkey`"

var repl = a.replace(/^(MATCH\s\d+)\s*/gm, "$1: ")
            .replace(/(\d+)\.\s+\[[^]]+\]\s*`([^`]*)`\s*/g, "[Group $1: $2]")
            .replace(/(?=MATCH\s\d+: )/g, "\n")

console.log(repl)

学习regex101演示，模式 /（\d +）\。\ s + \ [[^]] + \] \ * *`（[^`] *）`\ s * / g 将在PHP（PCRE）中正确替换 和Python ，但不在JavaScript上。

Studying regex101 demos, the pattern /(\d+)\.\s+\[[^]]+\]\s*`([^`]*)`\s*/g will replace properly in PHP (PCRE) and Python, but not on JavaScript.

为什么？

推荐答案

对于 PCRE 实现，一个关闭的方括号本身不需要转义，因为它是字符类中的第一个元字符。在JavaScript中， [^] 表示有效的字符类。

For PCRE implementations, a closing square bracket on its own does not need to be escaped since it is the first meta character inside of the character class. In JavaScript, [^] represents a valid character class.

引自 PCRE文档：

结束默认情况下，方括号本身并不特殊。但是，如果设置了 PCRE_JAVASCRIPT_COMPAT 选项，则
单独的结束方括号会导致编译时错误。如果作为该类的成员需要结束
方括号，它应该是该类中的
第一个数据字符（在初始抑扬符之后，如果
存在）或使用反斜杠转义。

A closing square bracket on its own is not special by default. However, if the PCRE_JAVASCRIPT_COMPAT option is set, a lone closing square bracket causes a compile-time error. If a closing square bracket is required as a member of the class, it should be the first data character in the class (after an initial circumflex, if present) or escaped with a backslash.

因此，您需要转义此字符。

Therefore, you need to escape this character.

/(\d+)\.\s+\[[^\]]+\]\s*`([^`]*)`\s*/g
               ^^

工作演示

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