jsonl as generators

jsonl.js

const fs = require('fs');
const readline = require('readline');

async function* readJsonlGen(filename) {
  const lineReader = readline.createInterface({
    input: fs.createReadStream(filename),
  });

  let i = 0;
  for await (const line of lineReader) {
    if (i === 0 && line === '') {
      continue;
    }
    yield JSON.parse(line);
    ++i;
  }
}

function* writeJsonlGen(filename) {
  const logger = fs.createWriteStream(filename, {
    flags: 'a',
  });

  while (true) {
    const o = yield;
    logger.write('\n' + JSON.stringify(o));
  }
}

module.exports = { readJsonlGen, writeJsonlGen };