expensive-function.js

var expensiveFn = _.profile(function(profileId) {
  var i = 0;

  // expensive loop
  while (i < 100) {
    arr = _.range(0, 50 * 1000);
    i++;
  }

  // expensive loop
  while (i < 200) {
    _.uniq(arr, 50 * 1000);
    i++;
  }
});

expensiveFn('123');