如何使用 csv-parse 避免等待...

Question

I am looking to be educated on this issue as I have spent a few days trying to resolve it on my own, to no avail.

I am using csv-parse to parse a CSV file.
I am using ESLint as my Linter
I am using the Airbnb JavaScript Style Guide plugin for ESLint
I am running this on the backend using NodeJS

My function is:

const { parse } = require('csv-parse');
const fs = require('fs');
const csvFile = 'myCsvFile.csv';

async function parseCsv(csvFile) {
  const records = [];
  const parser = fs.createReadStream(csvFile).pipe(parse({ delimiter: ',', columns: true }));
  for await (const record of parser) {
    records.push(record);
  }
  return records;

The function works well, however I am trying to abide by Airbnb's Style Guide, which does not like the for await...of loop as it is hitting me with the no-restricted-syntax violation.

I am curious on if there is a better way to write this to fall in line with Airbnb's Style Guide or, if this is one of those situations where it's OK to ignore the violation?

Answer 1

The styleguide says:

11.2 Don't use generators for now. Why? They don't transpile well to ES5.

Fortunately if you're using a recent NodeJS version, you don't need to transpile down, and can use the engine's native support. For browsers this advice is also outdated soon.

Answer 2

How about using events end returning promise?

async function parseCsv(csvFile) {
  return new Promise((resolve) => {
    const records = [];
    const stream = fs.createReadStream(csvFile);
    const parser = stream.pipe(parse({ delimiter: ',', columns: true }));
    
    parser.on('readable', () => {
      while (record = parser.read()) {
        records.push(record);
      }
    });

    let ended = false;

    parser.on('error', (error) => {
      console.error(error.message);
      if (!ended) {
        ended = true;
        resolve(records);
      }
    });

    parser.on('end', () => {
      if (!ended) {
        ended = true;
        resolve(records);
      }
    });
  });
}

Answer 3

Based on advice given in the answers, I am going to ignore the Airbnb Style Guide and use the Async iterator method.

Final code:

const { parse } = require('csv-parse');
const fs = require('fs');
const path = require('path');
const debug = require('debug')('app:csv:service');
const chalk = require('chalk');

async function parseCsv(csvFile) {
  try {
    const records = [];
    const stream = fs.createReadStream(csvFile);
    const parser = stream.pipe(parse({ delimiter: ',', columns: true }));
    // eslint-disable-next-line no-restricted-syntax
    for await (const record of parser) {
      records.push(record);
    }
    return records;
  } catch (error) {
    debug(`${chalk.red('Failed')} to parse CSV`);
    debug(`${chalk.red('ERROR:')} ${error}`);
    throw error;
  }
}

It may be time to find a new Style Guide to follow. Thank you to num8er for the code advice (I took one of your ideas to make my code a little more readable).