Read and modify data sequentially in node.js ?

• Yogesh Kumar
• 02-May-2022
• 0

P.S don't forget to handle errors by listening for the error event and rejecting the promise.

 function filterData(_file) {
  results = [];
  resultsFiltered = [];
  console.log('filtering');

  return new Promise((resolve) => {
    fs.createReadStream(dataFolder + _file)
      .pipe(csv())
      .on('data', (data) => results.push(data))
      .on('end', () => {
        // Filter results
        for (i = 0; i < results.length; i++) {
          if (results[i]['Points:2'] == 0) {
            resultsFiltered.push([
              results[i]['Points:0'],
              results[i]['Points:1'],
              results[i]['displacement:2'],
            ]);
          }
        }
        console.log('done');
        resolve(resultsFiltered)
      });
  });
}

const filesList = fs.readdirSync(dataFolder);

async function main() {
  for (i = 0; i < filesList.length; i++) {
    console.log(await filterData(filesList[i]));
  }
}

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