Spinal Tap Case Challenge

[jeremy0x]

function spinalCase(str) {
  str = str.replace(/([a-z])([A-Z])/g, "$1 $2");
  return str.split(/\s+|_+/).join("-").toLowerCase();
}

I need help with what "$1 $2" means in the second line of the code above. That line of code was from the challenge guide.

Link to the challenge:

freeCodeCamp.org

Link to the challenge guide

freeCodeCamp Challenge Guide: Spinal Tap Case

Spinal Tap Case Problem Explanation Convert the given string to a lowercase sentence with words joined by dashes. Relevant Links String global object JS Regex Resources JS String Prototype Replace JS String Prototype ToLowerCase Hints Hint 1 Create a regular expression for all white spaces and underscores. Hint 2 You will also have to make everything lowercase. Hint 3 The tricky part is getting the regular expression part to work, once you do that then just turn the uppercase to lowercase…

[sanity]

This challenge has it explained: https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/regular-expressions/use-capture-groups-to-search-and-replace

[jeremy0x]

Thank you for your reply. It’s clearer now.