How to skip header in csv and parse the column?

Question

let csv = require('fast-csv');
let fs = require('fs');
let readFileStream = fs.createReadStream(csvPath).setEncoding('utf-8');
let insList = [];
csv
    .fromStream(readStream, {headers: true})
    .on('data', function (data) {
        if (data[1] !== '' && insList.indexOf(data[1]) === -1 )
            insList.push(data[1]);

    })
    .on('end', function () {
        console.log(insList);
        console.log('done');
    })

The console.log(instList) line gives undefined when the {headers:true} is passed as argument to csv.fromStream. Why does that happen and how can I solve it?

If {headers:true} is not passed as argument the insList array gives the column name and all other unique elements in that column. I want the insList array to hold all unique items of column 1 (i.e. data[1]).

Leela Venkatesh K · Accepted Answer · 2022-05-31 11:09:25Z

2

Edit 31-May-2022:

Sample working code in repl.it

Before 31-May-2022(works for an older version of fast-csv)

I have found that it works fine. However, the only problem was that the data is an object not an array. I have tested with this csv.

title,count
a,1
b,2


c,3
d,4

The data was an object in format { title: 'a', count:'1'}.

const csv = require('fast-csv');
const fs = require('fs');

const readStream = fs.createReadStream('./test.csv').setEncoding('utf-8');
const insList = [];
csv
  .fromStream(readStream, { headers: true, ignoreEmpty: true })
  .on('data', function (data) {
    console.log('data === ', data);
    // major change is here
    if (data && data !== {}) insList.push(data);
    else console.log('empty data', data);
  })
  .on('end', function () {
    console.log('end => ', insList);
    console.log('done');
  })

Hope this helps

edited May 31, 2022 at 11:09

answered Jan 12, 2019 at 6:27

Leela Venkatesh K

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2 Comments

Ann Over a year ago

what do you mean data is an object? my data is a csv file.

Leela Venkatesh K Over a year ago

@ann I meant that the 'data variable' in callback is an object

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How to skip header in csv and parse the column?

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Before 31-May-2022(works for an older version of fast-csv)

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Before 31-May-2022(works for an older version of fast-csv)

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