Append:true doesn't create a file with headers

[peterpoliwoda]

When there is no csv in the directory and setting append to true the headers don't get added to the top of the file prior to including the data.

[artur-dani]

That is mention in documents

append (optional) Default: false. When true, it will append CSV records to the specified file. If the file doesn't exist, it will create one. NOTE: A header line will not be written to the file if true is given.

But is there any work around ?

[danifm1321]

I may come a little late, but what I did was check if the file I was about to write in was empty. If it was, I wrote the first line of data with the name of every header's field.

[mbitto]

The following can be used as workaround:

    const header = {id: name, title: name};
    const path = `/my/path`;
    let append = false;

    try {
        await fs.access(path);
        const st = await fs.stat(path);
        append = st.size > 0;
    } catch (e) { }

    const csvWriter = createObjectCsvWriter({
        path,
        append,
        header,
    })

[jonchurch]

I built off of mbitto's code and landed on this to dynamically set the append flag based on the existence of the output file:

const fs = require('fs').promises;
const path = require('path')

const createCsvWriter = require('csv-writer').createObjectCsvWriter;

const outputDirPath = path.resolve(__dirname, 'output')
const outputFilePath = path.join(outputDirPath, 'file.csv')

const header = [
  { id: 'date', title: 'DATE' },
  // ... your headers
];

async function createCsvWriterWithHeader() {
  let append = false

  try {
    await fs.access(outputFilePath);
    const st = await fs.stat(outputFilePath);
    append = st.size > 0;
  } catch (e) {
    // If the file doesn't exist or can't be accessed, we'll create a new one with headers
  }

  return createCsvWriter({
    path: outputFilePath,
    append,
    header,
  });

async function appendToCsv(metrics) {
  const csvWriter = await createCsvWriterWithHeader(); // Wait for the CSV writer to be configured
  await csvWriter.writeRecords([
    // your records
  ]);
}