[FEATURE] check Headers on read first row of file CSV

[lytaitruong]

• Formatting
• Parsing

Describe event:

• I have the file stream CSV from S3 and I have to read It by your API.
  The file Csv will have:

1. First row: name & type each column
2. Second row: Data on each column

The problem is:

• Instead using event.on('data') to check format the all database, it make i considers when the large row. I want just only using like event.on('headers') to return array first row to handle error before read all database.

Describe the solution you'd like
I see the library like 'csvtojson' or 'csv-parser' they have the event.on('header') to take the array of first row. If have it i can check and response for user the error.csv immediately to they fix
Or can option headers will matching the rule like custom Headers i see
csv.parse({ headers: (header, index) => if(header or index is invalid) => handle this row

Thank for your service

[doug-martin]

Thanks for the feature request! This is published under v4.1.0

[kaustavbhattacharjee]

Can I use the event.on('headers') in the fromPath function?
Example:

.on('headers',function(d){
        console.log(d);
      })