Regex string ends with not working in Javascript

Question

I am not very familiar with regex. I was trying to test if a string ends with another string. The code below returns null when I was expecting true. What's wrong with the code?

var id = "John"; var exists  ="blahJohn".match(/id$/); alert(exists); 

Answer 1

Well, with this approach, you would need to use the RegExp constructor, to build a regular expression using your id variable:

var id = "John"; var exists = new RegExp(id+"$").test("blahJohn"); alert(exists); 

But there are plenty ways to achieve that, for example, you can take the last id.length characters of the string, and compare it with id:

var id = "John"; var exist = "blahJohn".slice(-id.length) == id; // true