Implicit and Explicit Regex creation yield differe

问题:

I am searching on a largeish (500kb) document with a regex. I am using node.js (v0.10.13), but the behaviour is the same in Chrome (31) DevTools. With implicit regex creation I get what I expect to:

>/worker(?:.|\n)+Name:\s+(.+?)\s+Job title/.exec(text)
["worker   John Doe
                                                                 (s):
Name:                         Mrs Jean Smith          Job title", "Mrs Jean Smith"]

If I explicitly create a RegExp (which I need to do, since the expression can change at run-time) then it fails:

>new RegExp('worker(?:.|\n)+Name:\s+(.+?)\s+Job title').exec(text)
null

Why?

回答1:

When you create RegEx's with RegExp, you need to escape the special characters with double backslashes, like this

new RegExp('worker(?:.|\\n)+Name:\\s+(.+?)\\s+Job title').exec(text)