Simulador de rentabilidade no tesouro direto

simulator.js

import R from 'ramda'

const compoundInterest = (a, f, t) => a * (1 + f) ** t

const compoundInterestSerie = (a, f, t) => R.pipe(
  R.inc,
  R.range(0),
  R.map((i) => compoundInterest(a, f, i)),
  R.sum
)(t)

const totalInvested = R.multiply

const incomeTax = R.cond([
  [R.lte(R.__, 6),  R.always(0.225)],
  [R.lte(R.__, 12), R.always(0.200)],
  [R.lte(R.__, 24), R.always(0.175)],
  [R.T,             R.always(0.150)]
])

const simulateFixed = (a, f, t) =>
  a + (compoundInterest(a, f, t) - a) * (1 - incomeTax(t))

const simulateIncremental = (a, f, t) =>
  totalInvested(a, t) + (compoundInterestSerie(a, f, t) - totalInvested(a, t)) * (1 - incomeTax(t))

simulateFixed(5000, 0.00925, 60)
simulateIncremental(1000, 0.0095, 60)