Async of buffer perf test for mhofman

async-of-buffer.js

import { createReadStream } from 'fs';
import { arrayFromAsync } from 'iter-tools-es';

const COMMA = ','.charCodeAt(0);
const NL = '\n'.charCodeAt(0);

async function* csvParseChunks(document) {
  let row = [];
  let value = '';
  for await (const buffer of document) {
    for (let i = 0; i < buffer.length; i++) {
      const charCode = buffer[i];
      if (charCode === COMMA) {
        row.push(value);
        value = '';
      } else if (charCode === NL) {
        row.push(value);
        value = '';
        yield row;
        row = [];
      } else {
        value += String.fromCharCode(charCode);
      }
    }
  }
  row.push(value);
  yield row;
}

console.time('time');
const rows = await arrayFromAsync(csvParseChunks(createReadStream('./test.csv')));
console.log('rows:', rows.length);
console.timeEnd('time');