node_string_concat_vs_array_join_benchmark.js

gistfile1.js

var
  sys = require('sys'),
  chunk = "1234567890htcje,stdl",
  chunk_length = parseInt(process.ARGV[2]),
  count = parseInt(process.ARGV[3]),
  i;

function doBenchmark(title, execute_function) {
  var
    start,
    finish,
    data;
    
  start = new Date();
  execute_function();
  finish = new Date();
    
  sys.puts(title + ": " + Math.round(finish.valueOf() - start.valueOf()) + "ms");
}

function humanSize(size) {
  var suffix = "";
    
  if (size >= 1024) {
    suffix = "Kb";
    size /= 1024;
  }
  
  if (size >= 1024) {
    suffix = "Mb";
    size /= 1024;
  }
  
  return size + suffix;
}

// Generate chunk

sys.puts("Generate chunk...");

while (chunk.length < chunk_length) {
  chunk += chunk;
}

chunk = chunk.substr(0, chunk_length);

sys.puts("Chunk length: " + chunk_length + " bytes = " + humanSize(chunk_length));
sys.puts("Chunks count: " + count);
sys.puts("Content length: " + (chunk_length * count) + " bytes = " + humanSize(chunk_length * count));

// Benchmark 1: String concatenation

doBenchmark("String concatenation", function () {
  var content = "", i;
  for (i = 0; i < count; i += 1) {
    content += chunk;
  }
  content = content;
});

// Benchmark 2: Array join

doBenchmark("Array join", function () {
  var content = [], i;
  for (i = 0; i < count; i += 1) {
    content.push(chunk);
  }
  content = content.join('');
});