Unable to convert a string to the desired regexp in Javascript

Asked Apr 20 '17 at 05:36

Active Apr 20 '17 at 05:36

Viewed 28 times

I do have the following string:

"/^\d{4}$/"

which I want to convert to a RegExp to use the test method on it. However, simply doing :

var r = new RegExp("/^\d{4}$/") // returns : /\/^\d{4}$\//
r.test("4800") // returns false

isn't working.

I also tried the following :

var r = /^\d{4}$/
r.test("4800") // returns true

which is working

What am I missing here ? How to have it working in the first case with a string.

asked Apr 20 '17 at 05:36

Scipion

2

Remove `/` from start and end. RegExp adds it automatically. You need to pass pattern to it. So `new RegExp("^\d{4}$")` – Rajesh Apr 20 '17 at 05:37
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp – mplungjan Apr 20 '17 at 05:38
try this var r = new RegExp(/^\d{4}$/) – Srikanth B Apr 20 '17 at 05:42
1

`r=new RegExp("/^\\d{4}$/")` or just `r=/^\d{4}$/` As per documentation – mplungjan Apr 20 '17 at 05:45
Oh, come on. The right one with a constructor notation: `new RegExp("^\\d{4}$")`. Do not use `new RegExp(/^\d{4}$/)` as it is not supported in all browsers. – Wiktor Stribiżew Apr 20 '17 at 06:36

0 Answers0