Split string but keep delimiter

split.js

function split(string) {
  return string.match(/\w+(?:\s\w+)*\W?/g)
}

console.log(split("string one, string two, thing three, four four."))

// ["string one,", "string two,", "thing three,", "four four."]
// https://regex101.com/r/1mn4J9/1/