Question

I need to check JS matches for a dynamically generated string.

ie.

for(i=0; i< arr.length; i++)
{
 pattern_1="/part of "+arr[i]+" string!/i";

 if( string.search(pattern_1) != -1)
  arr_num[i]++;

}

However, this code doesn’t work – I presume due to the quotes. How do I do this?

Many thanks.

Answer 1

The /pattern/ literal only works as, well, a literal. Not within a string.

If you want to use a string pattern to create a regular expression, you need to create a new RegExp object:

var re = new RegExp(pattern_1)

And in that case, you would omit the enclosing frontslashes (/). These two lines are equivalent:

var re = /abc/g;
var re = new RegExp("abc", "g");