Please, look into this code. Why does creating of the same regular expression by different ways (by /regex/ literal and through RegExp constructor) cause different result? Why doesn't the second pattern match the whitespace in the str?

var str = " "; 

var pat1 = /\s/;
document.writeln(pat1.test(str)); // shows "true"

var pat2 = new RegExp("\s");
document.writeln(pat2.test(str)); // shows "false"

Can't find the answer on my question anywhere. Thanks

Please, look into this code. Why does creating of the same regular expression by different ways (by /regex/ literal and through RegExp constructor) cause different result? Why doesn't the second pattern match the whitespace in the str?

var str = " "; 

var pat1 = /\s/;
document.writeln(pat1.test(str)); // shows "true"

var pat2 = new RegExp("\s");
document.writeln(pat2.test(str)); // shows "false"

Can't find the answer on my question anywhere. Thanks

• javascript
• regex

1 Answer 1

You need to escape the backslash since it's in a string:

var pat2 = new RegExp("\\s");