How to use the fantasy-land.chainRec function in fantasy-land

function makeFLCompatible(constructor: any) {
  constructor.prototype[fl.of] = constructor[fl.of] = constructor.of
  constructor.prototype[fl.empty] = constructor[fl.empty] = constructor.empty
  constructor.prototype[fl.chainRec] = constructor[fl.chainRec] = constructor.chainRec
  constructor.prototype[fl.concat] = constructor.prototype.concat
  constructor.prototype[fl.map] = constructor.prototype.map
  constructor.prototype[fl.bimap] = constructor.prototype.bimap
  constructor.prototype[fl.ap] = constructor.prototype.ap
  constructor.prototype[fl.chain] = constructor.prototype.chain
}

function defAvailableMethods(Constructor) {
  const result = []
  if (Constructor[$.of]) result.push('of')
  if (Constructor[$.empty]) result.push('empty')
  if (Constructor[$.chainRec]) result.push('chainRec')
  if (Constructor[$.zero]) result.push('zero')
  if (Constructor.prototype[$.equals]) result.push('equals')
  if (Constructor.prototype[$.map]) result.push('map')
  if (Constructor.prototype[$.bimap]) result.push('bimap')
  if (Constructor.prototype[$.promap]) result.push('promap')
  if (Constructor.prototype[$.concat]) result.push('concat')
  if (Constructor.prototype[$.ap]) result.push('ap')
  if (Constructor.prototype[$.alt]) result.push('alt')
  if (Constructor.prototype[$.reduce]) result.push('reduce')
  if (Constructor.prototype[$.traverse]) result.push('traverse')
  if (Constructor.prototype[$.chain]) result.push('chain')
  if (Constructor.prototype[$.extend]) result.push('extend')
  if (Constructor.prototype[$.extract]) result.push('extract')
  return result
}