How to use variable to dynamically build regular expression object

Question

I want to build regular expression on the fly, like:

function buildReges(regex_string) {
   // here I want to use the string format to build a regex
   // like / + regex_string +/
}

I wonder how can I do that? Or if there is a way I can turn string into regular expression object?

@Amit THanks, Yes, this is JS, right now, what I can figure out is using JS Regex constructor, but I do not know how to specify /g /i — Kuan
– Kuan, Commented Oct 8, 2015 at 18:48

Amit · Accepted Answer · 2015-10-08 18:49:53Z

1

Use the RegExp constructor:

function buildReges(regex_string) {
   // here I want to use the string format to build a regex
   var re = new RegExp(regex_string);
}

if you want to use flags, you use a 2nd parameter:

new RegExp(regex_string, 'gi');

answered Oct 8, 2015 at 18:47

Amit

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2 Comments

Thanks, Yes, this is JS, right now, what I can figure out is using JS Regex constructor, but I do not know how to specify /g /i –

Thansk, this is helpful