Remove Last Comma from a string

Question

This will remove the last comma and any whitespace after it:

str = str.replace(/,\s*$/, "");

It uses a regular expression:

• The / mark the beginning and end of the regular expression

• The , matches the comma

• The \s means whitespace characters (space, tab, etc) and the * means 0 or more

• The $ at the end signifies the end of the string

you can remove last comma from a string by using slice() method, find the below example:

var strVal = $.trim($('.txtValue').val());
var lastChar = strVal.slice(-1);
if (lastChar == ',') {
    strVal = strVal.slice(0, -1);
}

Here is an Example

function myFunction() {
	var strVal = $.trim($('.txtValue').text());
	var lastChar = strVal.slice(-1);
	if (lastChar == ',') { // check last character is string
		strVal = strVal.slice(0, -1); // trim last character
		$("#demo").text(strVal);
	}
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>


<p class="txtValue">Striing with Commma,</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

function removeLastComma(str) {
   return str.replace(/,(\s+)?$/, '');   
}

The greatly upvoted answer removes not only the final comma, but also any spaces that follow. But removing those following spaces was not what was part of the original problem. So:

let str = 'abc,def,ghi, ';
let str2 = str.replace(/,(?=\s*$)/, '');
alert("'" + str2 + "'");
'abc,def,ghi '

https://jsfiddle.net/dc8moa3k/

In case its useful or a better way:

str = str.replace(/(\s*,?\s*)*$/, "");

It will replace all following combination end of the string:

1. ,<no space>
2. ,<spaces> 
3. ,  ,  , ,   ,
4. <spaces>
5. <spaces>,
6. <spaces>,<spaces>