dispatch.js

const R = require('ramda')
const { equals, T, cond, always, range } = R

/* dispatch by ramda */
function yaff (n) {
  return cond([
    [equals(0), always(1)],
    [equals(1), always(1)],
    [T, x => yaff(x - 1) + yaff(x - 2)],
  ])(n)
}

/* dispatch by conditional */
function fn (x) {
  return x === 0 ? 1
    : (x === 1) ? 1
      : fn(x - 1) + fn(x - 2)
}

/* dispatch by logical: cannot handle `falsy` return! */
function gn (x) {
  return ((x === 0) && 1) ||
    ((x === 1) && 1) ||
    (gn(x - 1) + gn(x - 2))
}