Getting Stuck on CamelCase to underscore

[abdulrahman.mhd.anas]

I’m solving CamelCase to underscore challenge on codewars site.
I pass all the tests except the random test.
So I need to know what are my mistakes on my code and what I should do to improve my code.
My code so far:

const toUnderScore = name => {
  return name.replace(/([a-z])([A-Z])|([A-Z])([A-Z])/g, "$1_$2").replace(/([A-Z])([A-Z])/g, "$1_$2").replace(/([A-Za-z])(\d{1,})/g, "$1_$2").replace(/(\d{1,})([A-Z])/g, "$1_$2");
}

Link to the challenge: Training on CamelCase to underscore | Codewars

[ilenia]

Have you tried debugging your code?

const toUnderScore = name => {
  let one = name.replace(/([a-z])([A-Z])|([A-Z])([A-Z])/g, "$1_$2")
  console.log(one)
  let two = one.replace(/([A-Z])([A-Z])/g, "$1_$2")
  console.log(two)
  let three = two.replace(/([A-Za-z])(\d{1,})/g, "$1_$2")
  console.log(three)
  let four = three.replace(/(\d{1,})([A-Z])/g, "$1_$2");
  console.log(four)
  return four
}
toUnderScore("oLq8_Wov_ZTb")

your first regex is eating away the ZT part (because those are actually the $3 and $4 capture groups, in that case $1 and $2 are just '' meaning that ZT is substituted with just _)
to have only two capture groups total, maybe you need to have the OR inside one of the capture groups

[abdulrahman.mhd.anas]

@ilenia

|([A-Z])([A-Z])/g

So this code part need a separate replace method
Am I correct?

[ilenia]

you could fix the regex, you don’t need an even different replace method

@ilenia

to have only two capture groups total, maybe you need to have the OR inside one of the capture groups