Introduction to csv-stream

The csv-stream library is a powerful tool for handling and processing CSV data streams in Node.js. With its simple API and efficient performance, it provides support for parsing large CSV files with ease. This library can be particularly useful for projects that require real-time data processing or handling of large datasets.

Installing csv-stream

 
  npm install csv-stream
 

Basic Usage

 
  const csvStream = require('csv-stream');
  const fs = require('fs');

  // Create a read stream from a file
  const readStream = fs.createReadStream('path/to/your.csv');

  // Initialize csv-stream parser
  const csvParser = csvStream.createStream();

  // Pipe the read stream into the parser
  readStream.pipe(csvParser).on('data', (data) => {
    console.log(data);
  });
 

Advanced API Examples

Handling Errors

 
  readStream.pipe(csvParser)
    .on('data', (data) => {
      console.log(data);
    })
    .on('error', (error) => {
      console.error('Error:', error.message);
    });
 

Transforming Data

 
  const transformStream = csvStream.createStream({
    transformRow: (row, callback) => {
      row.newColumn = 'transformed value';
      callback(null, row);
    }
  });

  readStream.pipe(transformStream).on('data', (data) => {
    console.log(data);
  });
 

Full Application Example

 
  const csvStream = require('csv-stream');
  const fs = require('fs');

  // Create a read stream from a file
  const readStream = fs.createReadStream('path/to/your.csv');

  // Create a csv-stream parser with a transformation function
  const csvParser = csvStream.createStream({
    transformRow: (row, callback) => {
      row.newColumn = row.oldColumn.toUpperCase();
      callback(null, row);
    }
  });

  // Pipe the read stream into the parser
  readStream.pipe(csvParser)
    .on('data', (data) => {
      console.log('Transformed Row:', data);
    })
    .on('end', () => {
      console.log('CSV file successfully processed');
    })
    .on('error', (error) => {
      console.error('Error:', error.message);
    });
 

Conclusion

The csv-stream library for Node.js is an excellent choice for developers looking to efficiently handle and process CSV data streams. Whether you are working with large datasets or require real-time processing, the provided APIs offer robust solutions for a variety of needs.

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