coeff.js

var fs = require('fs');
var csv = require('csv');
var _ = require('lodash');

var dir = './projection-coefficients/';
var out = 'coeff.json';
var obj = {};

function done() {
  var o = fs.createWriteStream(out, {encoding: 'utf8'});
  o.once('open', function(fd) {
    console.log(JSON.stringify(obj));
    o.write(JSON.stringify(obj)+'\n');
    o.end();
  });
}

fs.readdir(dir, function(err, files) {
  var c = 0;
  var fnames = files.reduce(function(a,f,i) {
    if (/\.csv$/.test(f)) a.push(f);
    return a;
  }, []);
  fnames.forEach(function(f) {
    var input = fs.createReadStream(dir.concat(f));
    var key = f.replace(/\..*/gi,'');
    input.on('data', function(d) {
      csv.parse(d.toString(), function(err, output) {
        var headers = output[0];
        headers.splice(0, 1, 'index');
        obj[key] = [];
        output.slice(1).forEach(function(l) {
          obj[key].push(_.zipObject(headers, l));
        });
        c += 1;
        if (c === fnames.length) done();
      });
    });
  });
});