stdin/stdout

Note: For WASM-enabled features in Node, Node.js 20.6+ is recommended (the WASM loader uses import.meta.resolve). On older Node versions, pass an explicit URL/Buffer to loadWASM().

Process CSV from stdin and output to stdout.

import { parseBinaryStream } from 'web-csv-toolbox';
import { Readable, Writable } from 'node:stream';

// Convert stdin to Web ReadableStream
const stdinStream = Readable.toWeb(process.stdin) as ReadableStream<Uint8Array>;

// Parse CSV from stdin
for await (const record of parseBinaryStream(stdinStream)) {
  // Output as JSON to stdout
  console.log(JSON.stringify(record));
}
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Usage:

# Pipe CSV file to script
cat data.csv | node script.js

# Or from curl
curl https://example.com/data.csv | node script.js
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Transform and output:

import { parseBinaryStream } from 'web-csv-toolbox';
import { Readable } from 'node:stream';

const stdinStream = Readable.toWeb(process.stdin) as ReadableStream<Uint8Array>;

console.error('Processing CSV from stdin...');

let count = 0;
for await (const record of parseBinaryStream(stdinStream)) {
  // Transform: convert to uppercase
  const transformed = Object.fromEntries(
    Object.entries(record).map(([k, v]) => [k, String(v).toUpperCase()])
  );

  // Output as CSV
  if (count === 0) {
    // Output header
    console.log(Object.keys(transformed).join(','));
  }
  console.log(Object.values(transformed).join(','));

  count++;
}

console.error(`Processed ${count} records`);
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