What are the minor problems that javascript regular expressions are easy to ignore?

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First, the special characters in brackets [] do not need to be escaped, such as [/], [.], [*], [?], [+] can directly match the corresponding characters\. *? +. Here are the test results:

So, / [\ d.] / this regular expression actually matches a numeric character or the character ".", which is equivalent to / [\ d\.] /

Second, the difference between match () and exec ()

The main difference between the two is that the regular expression has the global identifier g set.

If the global identifier g is not set, the result of calling string.match (regexp) is the same as that of calling regexp.exec (string)

However, when the global identifier g is set, string.match (regexp) puts all matches into the result array, and the result of regexp.exec (string) only gives the first successful match.

Instead, use the regexp.lastIndex attribute to record where the next match begins. The tests are as follows:

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