1. #!/usr/bin/env node
  3. const fs = require('fs');
  4. const path = require('path');
  5. const { program } = require('commander');
  7. program
  8. .version('1.0.0')
  9. .description('Truncate data in datasets for temporary use.')
  10. .requiredOption('-i, --input <file>', 'Path to the input dataset file (CSV or JSON).')
  11. .option('-o, --output <file>', 'Path to the output dataset file.')
  12. .option('-n, --numRows <number>', 'Number of rows to keep.', parseInt)
  13. .parse(process.argv);
  15. const options = program.opts();
  17. function truncateDataset(inputFile, outputFile, numRows) {
  18. try {
  19. let data;
  20. let fileType = path.extname(inputFile).toLowerCase();
  22. if (fileType === '.csv') {
  23. data = fs.readFileSync(inputFile, 'utf8').split('\n');
  24. data = data.slice(0, numRows); // Truncate CSV
  25. } else if (fileType === '.json') {
  26. data = JSON.parse(fs.readFileSync(inputFile, 'utf8'));
  27. if (Array.isArray(data)) {
  28. data = data.slice(0, numRows); // Truncate JSON array
  29. } else {
  30. console.error("JSON file does not contain an array.");
  31. process.exit(1);
  32. }
  33. } else {
  34. console.error('Unsupported file type. Only CSV and JSON are supported.');
  35. process.exit(1);
  36. }
  38. if (outputFile) {
  39. if (fileType === '.csv') {
  40. fs.writeFileSync(outputFile, data.join('\n'));
  41. } else if (fileType === '.json') {
  42. fs.writeFileSync(outputFile, JSON.stringify(data, null, 2)); //Pretty print JSON
  43. }
  44. } else {
  45. console.log(JSON.stringify(data, null, 2)); //Output to console if no output file is specified
  46. }
  47. } catch (err) {
  48. console.error('Error:', err.message);
  49. process.exit(1);
  50. }
  51. }
  53. truncateDataset(options.input, options.output, options.numRows);

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