d3.csv benchmark

csv-benchmark

#!/usr/bin/env node

var d3 = require("./");

var csv = ["foo", "bar", "baz", "foobarbaz", "BLAHBLAH"].join(",") + "\n" +
    d3.csv.formatRows(d3.range(10000).map(function() {
      return d3.range(5).map(Math.random);
    }));

benchmark("Slow", function() { parseSlow(csv); });
benchmark("Fast", function() { parseFast(csv); });
benchmark("JSON", function() { parseJSON(csv); });

function parseSlow(text, f) {
  var header, m = 0;
  return d3.csv.parseRows(text, function(row, i) {
    if (i) {
      var o = {}, j = -1;
      while (++j < m) o[header[j]] = row[j];
      return o;
    }
    header = row;
    m = header.length;
    return null;
  });
}

function parseFast(text, f) {
  var o;
  return d3.csv.parseRows(text, function(row, i) {
    if (o) return o(row, i - 1);
    var a = new Function("d", "return {" + row.map(function(name, i) {
      return JSON.stringify(name) + ": d[" + i + "]";
    }).join(",") + "}");
    o = f ? function(row, i) { return f(a(row), i); } : a;
  });
}

function parseJSON(text, f) {
  var o;
  return d3.csv.parseRows(text, function(row, i) {
    if (o) return o(row, i - 1);
    var a = function(d) {
      return JSON.parse("{" + row.map(function(name, i) {
        return JSON.stringify(name) + ":" + JSON.stringify(d[i]);
      }).join(",") + "}");
    };
    o = f ? function(row, i) { return f(a(row), i); } : a;
  });
}

function benchmark(name, f) {
  var observations = d3.range(20).map(function() {
    process.stdout.write(".");
    var start = process.hrtime();
    f();
    var elapsed = process.hrtime(start);
    return elapsed[0] * 1e3 + elapsed[1] / 1e6;
  });
  console.log("");
  console.log(name + ": " + Math.round(d3.mean(observations)) + "ms.");
}