endsWith in javascript

Question

How can I check if a string ends with a particular character in javascript? example I have a string say var str = "mystring#"; I want to know if that string str is ending with "#". How can I check it?

1. is there a endsWith() method in javascript?

2. one solution I have is take the length of the string and get the last character and check it.

Is this the best way or there is any other way?

Answer 1

You can add one if you like:

String.prototype.endsWith = function(str)
{
    return (this.match(str+"$")==str)
}

alert("markmac".endsWith(“mac”));

Should do it...

Answer 2

1. Unfortunately not.
2. if( "mystring#".substr(-1) === "#" ) {}

Answer 3

if( ("mystring#").substr(-1,1) == '#' )

-- Or --

if( ("mystring#").match(/#$/) )

Answer 4

There's nothing that a good piece of regexp and some prototype extension won't fix.

Include this in your script:

String.prototype.endsWith = function(str){return (this.match(str+"$")==str)}

After you include it you can use endsWith on any String.

Answer 5

all of them are very useful examples. Adding String.prototype.endsWith = function(str) will help us to simply call the method to check if our string ends with it or not, well regexp will also do it.

I found a better solution than mine. Thanks every one.

Answer 6

This version avoids creating a substring, and doesn't use regular expressions (some regex answers here will work; others are broken):

String.prototype.endsWith = function(str)
{
    var lastIndex = this.lastIndexOf(str);
    return (lastIndex != -1) && (lastIndex + str.length == this.length);
}

If performance is important to you, it would be worth testing whether lastIndexOf is actually faster than creating a substring or not. (It may well depend on the JS engine you're using...) It may well be faster in the matching case, and when the string is small - but when the string is huge it needs to look back through the whole thing even though we don't really care :(

For checking a single character, finding the length and then using charAt is probably the best way.

Answer 7

return this.lastIndexOf(str) + str.length == this.length;

does not work in the case where original string length is one less than search string length and the search string is not found:

lastIndexOf returns -1, then you add search string length and you are left with the original string's length.

A possible fix is

return this.length >= str.length && this.lastIndexOf(str) + str.length == this.length

Answer 8

/#$/.test(str)

will work on all browsers, doesn't require monkey patching String, and doesn't require scanning the entire string as lastIndexOf does.

Answer 9

Come on, this is the correct endsWith implementation:

String.prototype.endsWidth = function (s) {
  return this.length >= s.length && this.substr(this.length - s.length) == s;
}

using lastIndexOf just creates unnecessary CPU loops if there is no match.

Answer 10

I know this is a year old question... but I need this too and I need it to work cross-browser so... combining everyone's answer and comments and simplify it a bit:

String.prototype.endsWith = function(suffix) {
    return this.indexOf(suffix, this.length - suffix.length) !== -1;
};

• Doesn't create a substring
• Uses native indexOf function for fastest results
• Skip unnecessary comparisons using the second parameter of indexOf to skip ahead
• Works in Internet Explorer
• NO Regex complications

---

Also, if you don't like stuffing things in native data structure's prototypes, here's a standalone version:

function endsWith(str, suffix) {
    return str.indexOf(suffix, str.length - suffix.length) !== -1;
}

Answer 11

function check(str)
{
    var lastIndex = str.lastIndexOf('/');
    return (lastIndex != -1) && (lastIndex  == (str.length - 1));
}