collardeau

const pipe = require("ramda").pipe;   // node or webpack/browserify

const firstInitial = pipe(getFirstName, getFirstLetter);

collardeau

const getFirstName = name =>  { 
  if(name === null) return null;  // new
  return name.split(" ")[1]; 
}

const getFirstLetter = word => { 
  if(word === null) return null;  // new
  return word[0]; 
}

collardeau

const Maybe = val => ({
  val,
  fmap(f) {
    if(this.val === null) return Maybe(null);
    return Maybe(f(this.val));
  }
});

// lets create some containers with our Maybe factory
let user = Maybe("Slacker George McFly");

collardeau

const getFirstName = maybeName => maybeName.fmap(name => name.split(" ")[1]);
const getFirstLetter = maybeString => maybeString.fmap(string => string[0]);

collardeau

const getFirstName = person => person.split(" ")[1]; // second word
const getFirstLetter = string => string[0];   // first letter

const getFirstInitial = person => {
 return getFirstLetter(getFirstName(person));   // nested function!
}

// try it
getFirstInitial("Doc Emmett Brown");  // "E"

collardeau

// Standalone ES6 composition mentions "person" twice
const getFirstInitial = person => getFirstLetter(getFirstName(person))

// vs. Ramda's pipe composition
const firstInitial = pipe(getFirstName, getFirstLetter);

collardeau

const Maybe = val => ({
  val,
  fmap(f) {
    if(this.val === null || this.val === undefined) return Maybe(null);
    return Maybe(f(this.val));
  }
});

const getFirstName = maybeName => maybeName.fmap(name => name.split(" ")[1]);
const getFirstLetter = maybeString => maybeString.fmap(string => string[0]);

collardeau

const Maybe = val => {
  return {
    val: val,
    fmap: function(fn) {
      if(this.val === null) return Maybe(null);
      return Maybe(fn(this.val));
    }
  }
};

collardeau

// functor factory

const right = {
  of: val => functor(right, val),
  fmap: function(f){
    return right.of(f(this.val));
  }
}

const left = { 

collardeau

class Box {
  constructor(x) {
    this.value = x;
  }
  static of(x) {
    return new Box(x);
  }
  log() {
    console.log(this.value);
  }