[QUESTION] Why aren't these two statements equivalent?

[seguri]

Hi,
I'm new to the project and the Stream API. After spending too much time getting the first block below working, I was asking myself why it isn't equivalent to the second one. Could you kindly explain me what I'm doing wrong there?
Thanks!

Working:

const enhance = (filename) => {
  const inPath = path.join(__dirname, filename);
  const outStream = fs.createWriteStream(inPath.replace(".csv", ".transformed.csv"));
  parseFile(inPath, { headers: true })
    .transform(myTransformerFunction)
    .pipe(format({ headers: true }))
    .pipe(outStream);
};

Not working:

const enhance = (filename) => {
  const inPath = path.join(__dirname, filename);
  parseFile(inPath, { headers: true })
    .transform(myTransformerFunction)
    .pipe(writeToPath(inPath.replace(".csv", ".transformed.csv")));
};