[refactor.io] entry/2 - Decomposed Conditional

1 - before.js

if (date.before (SUMMER_START) || date.after(SUMMER_END))
  charge = quantity * _winterRate + _winterServiceCharge;
else
  charge = quantity * _summerRate;

2 - after.js

if (notSummer(date))
  charge = winterCharge(quantity);
else
  charge = summerCharge (quantity);

// helpers
function notSummer(date) {
  return date.before(SUMMER_START) || date.after(SUMMER_END);
}

function winterCharge(q) {
  return q * _winterRate + _winterServiceCharge
}

function summerCharge(q) {
  return q * _summerRate;
}

3 - manual.md

Original article: Refactoring: Decompose Conditional

Applicable for:

All languages and programming styles, but usually more applicable for imperative langauges.

Benefits:

Usually results in longer code but with much better readability.