I'm working on csv format to markdown, and have code something like this

document.querySelector("textarea.csv").addEventListener('input',(e) => {
  const convert = e.target.value
      .replaceAll(", ", " | ")
      .replace(/,\n/g, " |\n| ")
      .replace(/, \n/g, " |\n| ")
      .replace(/ \| \n/g, " |\n| ")
      .replace(/^[!\|]/g, "| ")
  
      
      
  console.log(
    convert
  );
  document.querySelector("textarea.markdown").value = "| " + convert;
})

But I think I missed the case to cover the line start from not "|", is there any way to check it?

The full code is here: https://codepen.io/dotku/pen/rNzOZLZ?editors=1010