Question

I am currently using the following JavaScript code:

concatedSubstring.replace(/\//g, '-').replace(/[A-Za-z]/g, function(c){
    return c.toUpperCase().charCodeAt(0)-64; 
});

…to take input in the format "1234/A", "22/B", etc. and output "1234-1" , "22-2", etc.

That is, / becomes -, and the letters become integers with A = 1, B = 2, etc.

I would like to change this so that if the input doesn’t contain a “/” the output will still insert a “-” in the spot where the “/” should’ve been. That is, the input "1234A" should output "1234-1", or "22B" should output "22-2", etc.

Answer 1

The following should work even for inputs containing more than one of your number/letter pattern:

var input = "1234/B 123a 535d";

var replaced = input.replace(/(\d+)(\/?)([A-Za-z])/g, function(m,p1,p2,p3) {
   return p1 + "-" + (p3.toUpperCase().charCodeAt(0)-64);
});

alert(replaced); // "1234-2 123-1 535-4"

The regex:

/(\d+)(\/?)([A-Za-z])/g

…will match one or more digits followed by an optional forward slash followed by a single letter, capturing each of those parts for later use.

If you pass a callback to .replace() then it will be called with arguments for the full match (which I’m ignoring for your requirement) and also for any sub-matches (which I use).