Event processing loop is broken in case of exceptions

[luav]

The lack of the proper exception handling in CsvParser breaks the event loop of NodeJs, resulting in the exception that can not be handled anywhere upper in the call stack:

events.js:174
      throw er; // Unhandled 'error' event
      ^

Error: Invalid Record Length: columns length is 10, got 3 on line 42
    at Parser.__onRecord (/media/truecrypt1/projects/consulting/zazuko/csv-validate/node_modules/csv-parse/lib/index.js:783:9)
    at Parser.__parse (/media/truecrypt1/projects/consulting/zazuko/csv-validate/node_modules/csv-parse/lib/index.js:660:40)
    at Parser._transform (/media/truecrypt1/projects/consulting/zazuko/csv-validate/node_modules/csv-parse/lib/index.js:467:22)
    at Parser.Transform._read (_stream_transform.js:190:10)
    at Parser.Transform._write (_stream_transform.js:178:12)
    at doWrite (_stream_writable.js:415:12)
    at writeOrBuffer (_stream_writable.js:399:5)
    at Parser.Writable.write (_stream_writable.js:299:11)
    at CsvParser._transform (/media/truecrypt1/projects/consulting/zazuko/csv-validate/lib/CsvParser.js:65:19)
    ...

The outlined unhandled exception is not catched by both async .catch( (err) = {} ) and sync try { ... } catch (err) { }, for example in the following code:

for (const filename in filesInfo) {
        // Handle the file
        try {
          await parseFile(filename, { relaxColumnCount, skipErrorLines, delimiter, quotes, newLine, encoding }, ...
          ).catch((err) => {
            console.error(`ERROR in ${filename}: ${err}`) // err.stack
          })
        } catch (err) {
          // Note: this should never happen if CsvParser works correctly
          console.error(`ERROR SYNC in ${filename}: ${err}`)
        }
      }

Exceptions in _transform should be forwarded to its callback (see the original csv-parse code for the reference) as follows:

  _transform (chunk, encoding, callback) {
    try {
      this.parser.write(chunk, encoding, callback)
    } catch(err) {
      callback(err)
    }
  }

Then, any exceptions in _transform can be handled properly by the async .catch( (err) = {} ).

The respective test for CsvParser is available in csv-validate.

[bergos]

Thanks for reporting. Fixed in #30 .