gist for first blog post

writerMonadFizzBuzz.js

const makeMonad = (prevData, prevLog) => fn => { 
   const newData = fn(prevData).data;
   const newLog = prevLog + fn(prevData).log; 
   return { data: newData,
           log: newLog,
           bind: makeMonad(newData, newLog) 
    };
};

const pure = x => ({
   data: x,
   log: "",
   bind: makeMonad(x, "")
})

const withLog = (x, stuffToWrite) => pure(x).bind(x => ({data: x, log: stuffToWrite}))

const makeFizzBuzzQuxxPiece = (test, thingsToWrite) => (x) => test(x) ? withLog(x, thingsToWrite) : pure(x)

const theFizz = makeFizzBuzzQuxxPiece(x => x % 3 === 0, "Fizz")
const theBuzz = makeFizzBuzzQuxxPiece(x => x % 5 === 0, "Buzz")
const theQuxx = makeFizzBuzzQuxxPiece(x => x % 7 === 0, "Quxx")

const range = (low, high) =>  Array(high - low + 1).fill(0).map((_, i) => i + low);
const thePrimer = makeFizzBuzzQuxxPiece(x => x > 1 && range(2, x-1)
.every(divisor => x % divisor !== 0), "prime")

const fibExtract = ({data, log}) => log ? log: data;

range(1, 1000).forEach(x => {
   console.log(fibExtract(pure(x)
   .bind(thePrimer)
   .bind(theFizz)
   .bind(theBuzz)
   .bind(theQuxx)
))})