How to remove the last comma of a string in JavaScript

In this tutorial, we are going to learn about how to remove the last character of a given string in JavaScript.

Consider, we have the following string with multiple commas:

const str = "a,b,c,";

Now, we want to remove the last comma from the above string.

Removing the last comma

To remove the last comma of a string in JavaScript, we can use the built-in slice() method by passing the 0, -1 as arguments to it.

In the slice() method, negative indexes are used to access the characters from the end of a string.

Here is an example, that removes the last comma from the following string.

const str = "a,b,c,";
const result = str.slice(0, -1);

console.log(result);

Output:

"a,b,c"

In the example above, we have passed 0, -1 as arguments to the slice() method. so it begins the extraction at index position 0, and extracts before the last character of a string.

Similarly, we can also use the substring() method to remove the last comma of a string.

const str = "a,b,c,";
const result = str.substring(0, str.length-1);

console.log(result);

In the above code, we have passed two arguments to the substring() method, the first one is start index 0 and the second one is the end index (which is not included in the final output).

Note: The slice() and substring() methods does not modify the original string.