CODEWITHSUNDEEP
javascriptnode.jscsv
Rodrigo5244
Rodrigo5244

Reputation: 5525

How do I add rows with node-csv?

I know I can modify rows using the following code:

const data = fs.createReadStream('api.csv')
  .pipe(csv.parse({columns: true}))
  .pipe(csv.transform(record => {
    // can modify row here
    return record;
  }));
  .pipe(csv.stringify({header: true}))
  .pipe(process.stdout);

But how do I add new rows? I think I have to write data to the pipeline, probably before csv.stringify, but I am not sure how to.

Upvotes: 1

Views: 494

Answers (2)

Diomidis Spinellis
Diomidis Spinellis

Reputation: 19345

If the data to be added depends on the input data, as you indicated in your original question, you can call the transform with a callback function. For example, the following will duplicate each record.

const data = fs.createReadStream('api.csv')
  .pipe(csv.parse({columns: true}))
  .pipe((data, callback) => setImmediate(() => callback(null, data, data))))
  .pipe(csv.stringify({header: true}))
  .pipe(process.stdout);

Upvotes: 1

Rodrigo5244
Rodrigo5244

Reputation: 5525

I can write to the stream returned by the pipe method between the transform and stringify.

const data = fs.createReadStream('api.csv')
  .pipe(csv.parse({columns: true}))
  .pipe(csv.transform(record => {
    // can modify row here
    return record;
  }));

// Can add rows here
data.write({
  col1: 1,
  col2: 2
});

data.pipe(csv.stringify({header: true})).pipe(process.stdout);

Upvotes: 0

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