Regex to make nondecimal number decimal (add .00)

Question

I have an user input where user can edit price of something. To leave data consistance I would like to manipulate with that string on front-end site.

What I want to do is:

1234 to 1234.00
12.3 to 12.30
12,3 to 12.30
1234.45 to 1234.45

So basicly,

1. Replace comma with dots this should be done easy with somehing like:

   str.replace(',', '.');
   

2. Add dots if number if not decimal and also always change number of digits on two(so add 0 if needed) I try to do something like:

   priceByUser = priceByUser.replace(/^\d*\.?\d*$/, "$1\.00");
   

unfortunately this really doesnt even work as I expected.

Is there a chance someone can help me to solve this issue? Thanks

Answer 1

You could consider using a regular expression to replace your commas and periods with just decimal points and then parse the values as floats via parseFloat() then finally, use the toFixed(2) function to indicate that you want two decimal places :

// This will clean up your input (consolidating periods and commas), parse the result
// as a floating point number and then format that number to two decimal places
priceByUser = parseFloat(priceByUser.replace(/,/g,'.')).toFixed(2);

If you wanted an extra-level of validation, you could consider stripping out any non-digit or decimal places after this occurs :

// Sanitize
priceByUser = priceByUser.replace(/,/g,'.').replace(/[^\d\.]/g,'');
// Parse and format
priceByUser = Number(priceByUser).toFixed(2);

Example

You can see a working example here and and example of input/output below :