gistfile1.js

var Immutable  = require("immutable"),
    t          = require("transducers-js"),
    comp       = t.comp,
    map        = t.map,
    filter     = t.filter,
    transduce  = t.transduce;
 
var inc = function(n) { return n + 1; };
var isEven = function(n) { return n % 2 == 0; };
var sum = function(a,b) { return a+b; };
 
// faster with transducers
var xf = comp(map(inc),filter(isEven));
 
var largeVector = Immutable.Vector();
var largeArray = [];
 
for(var i = 0; i < 10000000; i++) {
    largeVector = largeVector.push(i);
    largeArray.push(i);
}
 
console.time('Array map -> filter -> reduce');
largeArray.map(inc).filter(isEven).reduce(sum);
console.timeEnd('Array map -> filter -> reduce');
 
console.time('Array using Transducers');
transduce(xf, sum, 0, largeArray);
console.timeEnd('Array using Transducers');
 
console.time('Immutable.js vector map -> filter -> reduce');
largeVector.map(inc).filter(isEven).reduce(sum);
console.timeEnd('Immutable.js vector map -> filter -> reduce');
 
console.time('Immutable.js using Transducers');
transduce(xf, sum, 0, largeVector);
console.timeEnd('Immutable.js using Transducers');

console.time('Array reduce');
largeArray.reduce(function(sum, item) {
  const plus1 = item + 1;
  return (plus1 % 2 === 0) ? sum + plus1 : sum;
}, 0);
console.timeEnd('Array reduce');

console.time('Naive for loop');
var sum = 0;
for(var i = 0; i < largeArray.length; i++) {
  var plus1 = largeArray[i] + 1;
  if (plus1 % 2 === 0)
   sum = sum + plus1;
}
console.timeEnd('Naive for loop');

Array map -> filter -> reduce: 2037ms
Array using Transducers: 489ms
Immutable.js vector map -> filter -> reduce: 712ms
Immutable.js using Transducers: 759ms
Array reduce: 512ms
Naive for loop: 19ms