Combine a few regular expressions

Question

I have a string that I need to change using regex. So tried a lot of different things, and this is how close I came. Below are a few examples of what the string can be and what it that case the result should be:

case A: "Schoenen US 30 / " should become -> "30"
case B: "Dames US 30 / " should become -> "US 30"
case C: "Dames US w30 / " should become -> "US 30"
case D: "Heren US w30 / L34" should become -> "US 30 / 34"
case E: "Dames US L / " should become -> "US L"

So what I need to do is: 1. match the part: "Schoenen US ","Dames " and "Heren " (so including end space). 2. match any "w","W","l" and "L" in the string (need to be removed) 3. match " / " only on the end of string (if it exists)

So what I came up with:

case A: "/\b(Dames[ ]|dames[ ]|Heren[ ]|heren[ ]|Schoenen US[ ]|[WwLl]).([0-9][0-9]).(\/ )/g" with substitution "$2"
case B & C: "/\b(Dames[ ]|dames[ ]|Heren[ ]|heren[ ]|Schoenen US[ ]|[WwLl]| \/ )/g" with empty substitution
case D: "/\b(Dames[ ]|dames[ ]|Heren[ ]|heren[ ]|Schoenen US[ ]|[WwLl])/g" with empty substitution
case E: No idea how to do this

These regular expressions do what I want (except for the case E ofcourse). But the problem is that I can only use one regex, so I somehow need to combine all 4 of them. I am a complete beginner when it comes to regex, so if anyone can point me in the right direction would be awesome.

Answer 1

Try to merge all cases to single pattern as close as possible

 function tr(str) {
   return str.replace(/(?:Schoenen US |\w+ (US ))(?:[wW]?(\d+ \/ )[lL]?(\d+)|[wW]?(\d+) \/ |([lL]) \/)\s*$/, "$1$2$3$4$5");
 }

 console.log(tr("Schoenen US 30 / ")); // 30
 console.log(tr("Dames US 30 / ")); // US 30; 
 console.log(tr("Dames US w30 / ")); //US 30
 console.log(tr("Heren es US w30 / L34")); // US 30 / 34
 console.log(tr("Dames US L / ")); // US L

Hope this will help you to understand regex