Generating a map rather than an object?

[mbostock]

What if a column is named __proto__?

[mbostock]

This seems quite unlikely in practice and not worth worrying about—and besides, you can always use parseRows and create a map yourself. Something like:

var columns, data = d3_dsv.csv.parseRows(text, function(row, i) {
  if (i) {
    var m = d3_array.map();
    columns.forEach(function(c, i) { m.set(c, row[i]); });
    return m;
  } else {
    columns = row;
  }
});