Finding the most frequently used word in sttring without including spaces

I found this code in StackOverflow which takes a string and finds the most used word in said string.

However it does not omit spaces as a common word. I have no idea how, but how could this code be revised inorder for it to not include the spaces as a character?

I was thinking that I could write a if-statment that would omit the space as a common word. But I have no idea on how to write it?

This is the code below:

let str = "She she sells sea shells down by the sea shore boop seasalt"

function commonWord() {
  if (str.length === 0) {
    return null
  }

  str = str.toLowerCase()
  let maxCount = 0
  let maxWord = []
  str = str.split(" ")
  str.forEach(word => {
    let wordValue = str.filter(w => w === word).length

    if (wordValue > maxCount) {
      maxCount = wordValue
      maxWord.length = 0
      maxWord.push(word)
    } else if (wordValue == maxCount) {
      maxWord.push(word)
    }
  })
  console.log(maxWord)
}
commonWord()

Any help would be greatly appriciated!