How can I test if a string the last “part” of another string?

Question

var longString = "this string is long but why"
var shortString = "but why"

How can i test if shortString is the not only contained in longString but it is actually the last part of the string.

I used indexOf == 0 to test for the start of the string but not sure how to get the end of it

Miasma

javascript im assuming? – Prolegomenon

Which programming language are you using and what have you tried so far ? Further, this case can be solved with a simple "substring" - why do you want to use regex which is way inferior from performance perspective ? – Proa

sorry yes it is javascript – Miasma

Answer 1

You don't need regex, if it is javascript you can just do:

longString.endsWith(shortString)

Keane

endsWith() seems to be added with an external library. – Prolegomenon

Ignore that comment. This has been added to the ECMAScript 6 specification. Not all javascript implementations may support it yet however. developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… – Prolegomenon

Well, for the time being, you can use a polyfill library such as the ones mentioned in ES6-tools – Hass

Answer 2

You can use the following if you need regex:

var matcher = new RegExp(shortString + "\$", "g");
var found = matcher.test(longString );

Inaccessible

The $ should need to be escaped. Also shouldnt need to globally check on a single line. – Prolegomenon

Answer 3

You can build a regex from shortString and test with match:

var longString = "this string is long but why";
var shortString = "but why";
// build regex and escape the `$` (end of line) metacharacter
var regex = new RegExp(shortString + "\$");
var answer = regex.test(longString);
// true
console.log(answer);

Hope this helps

Prolegomenon