javascript正则表达式/ e * /结果为空匹配

Question

Why the javascript regular expression

/e*/ 

cannot match any part of the string "hello"?

I have already tried the following

"hello".match(/e*/)     //return [""]

while /e+/ can match

"hello".match(/e+/)     //return ["e"]

Am I overlooking any simple stuff????

Answer 1

It matched, or you would be getting null as a result.

The match is zero characters right at the beginning of the string. Your assertion is "find a place in the string where there is zero or more of e ": Right at the start of the hello , there is zero or more of e , so we don't need to search further. match expectedly returns [""] (the zero characters matched).

On the other hand, /e+/ wants one or more e characters; this is not satisfied at the start of the string, but it is satisfied at the very next position, and you get ["e"] .