ddanielbee

const Nothing = () => ({
  isJust: () => false,
  fold: (b, f) => b,
  inspect: () => `Nothing`
});

const Just = x => ({
  isJust: () => true,
  fold: (b, f) => f(x),
  inspect: () => `Just${x}`

ddanielbee

const jsc = require("jsverify");

// Necessary Utils
const id = x => x;

const compose = (...fns) => x => fns.reduceRight((v, f) => f(v), x);

// Functor Properties
const functorIdentity = f => f.fmap(id).toString() === f.toString();

ddanielbee

const jsc = require("jsverify");

// Write a function that:
// Takes an array of strings
// Removes all instances of a dash character (-)
// Makes sure concatenating the strings will result in a string
// shorter than 200 characters
// (by removing all extra fluff from the tail)
// Makes all strings lowercase
// Returns an array of the resulting strings.

ddanielbee

const NOTHING = {};

const safeProperty = (obj, propertyName) => (obj[propertyName] ? obj[propertyName] : NOTHING);

const recurProperties = (obj, ...propertyNames) =>
  propertyNames.reduce(
    (accValue, currentProperty) =>
      accValue[currentProperty] ? accValue[currentProperty] : NOTHING,
    obj
  );

ddanielbee

// Utils

const fantasyConcat = (semiOne, semiTwo) => {
  if (
    semiOne.instances &&
    semiTwo.instances &&
    semiOne.instances.includes("Semigroup") &&
    semiTwo.instances.includes("Semigroup")
  )
    return semiOne.concat(semiTwo);