Regex to add a space after each comma in Javascript

Question

I have a string that is made up of a list of numbers, seperated by commas. How would I add a space after each comma using Regex?

Answer 1

I find important to note that if the comma is already followed by a space you don't want to add the space:

"1,2, 3,4,5".replace(/,(?=[^\s])/g, ", ");
> "1, 2, 3, 4, 5"

This regex checks the following character and only replaces if its no a space character.

Answer 2

Another simple generic solution for comma followed by n spaces:

"1,2, 3,   4,5".replace(/,[s]*/g, ", ");
> "1, 2, 3, 4, 5"

Always replace comma and n spaces by comma and one space.

Answer 3

Those are all good ways but in cases where the input is made by the user and you get a list like "1,2, 3,4, 5,6,7"

..In which case lets make it idiot proof! So accounting for the already formatted parts of the string, the solution:

"1,2, 3,4, 5,6,7".replace(/, /g, ",").replace(/,/g, ", ");

//result: "1, 2, 3, 4, 5, 6, 7" //Bingo!

Answer 4

var numsStr = "1,2,3,4,5,6";
var regExpWay = numStr.replace(/,/g,", ");
var splitWay = numStr.split(",").join(", ");

Answer 5

Don't use a regex for this, use split and join.

It's simpler and faster :)

'1,2,3,4,5,6'.split(',').join(', '); // '1, 2, 3, 4, 5, 6'

Answer 6

As I came here and did not find a good generic solution, here is how I did it:

"1,2, 3,4,5".replace(/,([^\s])/g, ", $1");

This replaces comma followed by anything but a space, line feed, tab... by a comma followed by a space.

So the regular expression is:

,([^\s])

and replaced by

, $1