writing matched lines with node js in CSV

Question

Am taking baby steps with node js. First task, read a delimited file line by line, and spit out the lines that contain the string "imputed".

#!/usr/bin/env node

var Csv = require("csv"),
    Fs = require("fs");

var foods = "/../data/sr26";


    Csv()
        .from.stream(
            Fs.createReadStream(__dirname + foods + "/SRC_CD.txt"),
            {"delimiter": "^", "quote": "~"}
        )
        .to(function(data, count) {
            console.log(data);
        })
        .transform(function(row, index, callback) {
            //if (row[1].search(/imputed/) != -1) {
                process.nextTick(function() {
                     callback(
                        null, 
                        row[1].substr(0, 15) + "… " + row[1].search(/imputed/) + "\n"
                    )
                });
            //}
        });

Prints out

Analytical or d… -1
Calculated or i… 14
Value manufactu… -1
Aggregated data… -1
Assumed zero… -1
Calculated from… -1
Calculated by m… -1
Aggregated data… -1
Manufacturer's … -1
Analytical data… -1

But uncommenting the comparison inside transform results in no output at all. What am I doing wrong?

Ilan Frumer · Accepted Answer · 2014-01-20 00:33:43Z

1

When using csv transform method asynchronously, you must invoke the callback.
If you invoke it with null, the record will simply be skipped.

if (row[1].search(/imputed/) != -1) {

  process.nextTick(function() {
    callback(
      null, 
      row[1].substr(0, 15) + "… " + row[1].search(/imputed/) + "\n"
    )
  });

} else {
  callback(null, null);
}

answered Jan 20, 2014 at 0:33

Ilan Frumer

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