Extracting data from a string jquery

Question

I have e scenario like this: I need to build a jQuery function that takes a string as an input and update the string into another string. The input can be one of these:

• A="0"
• A="0, 5" (basically can be "0, any_other_digits_different_from_0")
• A="0, 58"
• A="58" (basically any number that doesn't start with zero)

I want the function to updated to:

• if input is option number one (A="0") update A="--"
• if input is option number two (A="58") DO NOTHING, leave it A="58"
• if input is option number three (A="0, 5" update to A="5"
• if input is option number four (A="0, 58") update to A="58"

Option four can have more than two digits after "0, ".

It seems like this can be done by regex somehow but I am not being able to put anything together that can make it work. Any help is appreciated.

Answer 1

You could split the string and take the last value. If zero return '--'.

function getValue(a) {
    return (+a.split(', ').pop() || '--').toString();
}
 
console.log(getValue("0"));     // "--"
console.log(getValue("0, 5"));  // "5"
console.log(getValue("0, 58")); // "58"
console.log(getValue("58"));    // "58"

A proposal with a regular expression searching for last numbers

function getValue(a) {
    return (+a.match(/\d+$/) || '--').toString();
}
 
console.log(getValue("0"));     // "--"
console.log(getValue("0, 5"));  // "5"
console.log(getValue("0, 58")); // "58"
console.log(getValue("58"));    // "58"