Remove last appeared comma in string using javascript

Question

I have a text

test, text, 123, without last comma

Need it to be

test, text, 123 without last comma

(no comma after 123). How to achieve this using javasctipt?

Solution 1

str.replace(/,(?=[^,]*$)/, '')

This uses a positive lookahead assertion to replace a comma followed only by non-commata.

Solution 2

A non-regex option:

var str = "test, text, 123, without last comma";
var index = str.lastIndexOf(",");
str = str.substring(0, index) + str.substring(index + 1);

But I like the regex one. :-)

Solution 3

Another way to replace with regex:

str.replace(/([/s/S]*),/, '$1')

This relies on the fact that * is greedy, and the regex will end up matching the last , in the string. [/s/S] matches any character, in contrast to . that matches any character but new line.