Question

我对以下正则表达式的错误感到非常难过：

var // this regex digests a string into leading whitespace,
    // content text, and trailing whitespace.
    lineRegex = /^(\s*)(\S.*\S|\S)?(\s*)$/g,
    /* ... */;

lineRegex应匹配任何。甚至没有一个必需的字符，如果字符串中有字符，则它们都是空格或不是空格。当我将完全正则表达式粘贴到FireBug控制台并添加.exec("")时，我得到了预期的结果["", "", undefined, ""]。但在我的JSFiddle（http://jsfiddle.net/Lay9k/9/）中我有：

try {
    var sections = lineRegex.exec(lineTxt),
        rawLeadingWs = sections[1] || "",
        contentText = sections[2] || "",
        importantTabs = rawLeadingWs.replace(
            oneTabWorthOfSpaces, "\t"
        ),
        tabsAndAligningSpaces =
            aligningTabRegex.exec(importantTabs),
        // I don't like this as much as Lint does.
        importantWsLength = 
            (tabsAndAligningSpaces[1] || "").replace(/[^\t]/g, "")
            .length * spacesPerTab +
            (tabsAndAligningSpaces[2] || "").length;
} catch (wtf) {
    console.log({
        lineText: lineTxt,
        sections: sections,
        rawLeadingWs: rawLeadingWs,
        contentText: contentText,
        importantTabs: importantTabs,
        tabsAndAligningSpaces: tabsAndAligningSpaces,
        importantWsLength: importantWsLength
    });
    throw wtf;
}

当sections is null为lineTxt时，我得到""。那是什么给出了什么？

Answer 1

我认为问题在于正则表达式的lastIndex属性未正确重置。

以下是相关问题：Why does Javascript's regex.exec() not always return the same value?

来自其中一个答案的

reg.lastIndex = 0;似乎解决了这个问题。

JS RegExp在FireBug中匹配......但不是JSFiddle？

1 个答案: