How do I match a number inside square brackets with regex

Question

I wrote a regular expression which I expect should work but it doesn\'t.

  var regex = new RegExp(\'(?<=\\[)[0-9]+(?=\\])\')

Javascript

Answer 1

To increment multiple numbers in the form of lets say:

var str = '/a/b/[123]/c/[4567]/[2]/69';

Try:

str.replace(/\[(\d+)\]/g, function(m, p1){
 return '['+(p1*1+1)+']' }
)

//Gives you => '/a/b/[124]/c/[4568]/[3]/69'