JavaScript Regex捕获并替换可选部分

Question

我发现很难在JavaScript使用Regex对以下行执行Capture and Replace ：

// Lines:
This is <span>foo</span>.
This is <span>(Capital) foo</span>.
This is <span>foo (Plural)</span>.
This is <span>(Capital) foo (Plural)</span>.

我需要This is foo. 以上所有。

我尝试为：

var pattern = /<span>(\(Capital\))?\s?(\w+)\s?(\(Plural\))?<\/span>/;

var text1 = "This is <span>foo</span>";
var text2 = "This is <span>(Capital) foo</span>";
var text3 = "This is <span>foo (Plural)</span>";
var text4 = "This is <span>(Capital) foo (Plural)</span>";

text1.replace(pattern, function(_, m){ return m; });
text2.replace(pattern, function(_, m){ return m; });
text3.replace(pattern, function(_, m){ return m; });
text4.replace(pattern, function(_, m){ return m; });

但是它不起作用。

Answer 1

如果<>或()之间的内容无关紧要，则：

text.replace(/[<(][^>)]+[>)]/g, '').replace(/ {2,}/g, ' ');

（添加了第二个替换项，确保没有多余的空格留在后面）

Answer 2

您可以使用以下正则表达式，

<span>(?:\(Capital\))?\s*(\w+)\s*(?:\(Plural\))?<\/span>

将匹配的字符替换为组索引1中的字符。

演示

> "This is <span>foo</span>.".replace(/<span>(?:\(Capital\))?\s*(\w+)\s*(?:\(Plural\))?<\/span>/g, '$1');
'This is foo.'
> "This is <span>(Capital) foo</span>.".replace(/<span>(?:\(Capital\))?\s*(\w+)\s*(?:\(Plural\))?<\/span>/g, '$1');
'This is foo.'
> "This is <span>foo (Plural)</span>.".replace(/<span>(?:\(Capital\))?\s*(\w+)\s*(?:\(Plural\))?<\/span>/g, '$1');
'This is foo.'
> "This is <span>(Capital) foo (Plural)</span>.".replace(/<span>(?:\(Capital\))?\s*(\w+)\s*(?:\(Plural\))?<\/span>/g, '$1');
'This is foo.'

Answer 3

您可以将正则表达式修改为：

var r = str.replace(/(?:</?span>| *\((?:Capital|Plural)\)) */gmi, "");

正则演示