xiaoyunyang

//Currying is when you break down a function that takes multiple arguments into a //series of functions that take part of the arguments.
//converts a function f of two arguments into a function of one argument that partially applies f.
  def curry[A,B,C](f: (A,B) => C): A => (B => C) =
  		(a: A) => (b: B) => f(a,b)  
  //> curry: [A, B, C](f: (A, B) => C)A => (B => C)

xiaoyunyang

import express from  'express'
import path from 'path'
import fs from 'fs'

const app = express()
app.set("port", process.env.PORT || 3001)

// Middleware that serves static file ======================================

app.use('/static', (req, res, next) => {

xiaoyunyang

function Person(name) {
   var secret = “secret!”
   this.name = name
   this.setName = function(newName) { this.name = newName }
   this.setNameToFoo = function() { this.name = foo }
   this.getSecret = function() { return secret }
}
 
var a = new Person(“Max”)
 

xiaoyunyang

var incrementUntil = function(max) { 
   if(num >= max) return num 
   num++
   incrementUntil(max)
}
 
var num = 0
incrementUntil(3)
num //> 3

xiaoyunyang

num = 0
var myFun = function() { 
   incrementUntil(3)
    return num 
}

myFun() //> 3
num //> 3

xiaoyunyang

num = 0
var myFun2 = function() { 
   var num = -1
   incrementUntil(3)
  return num 
}

myFun2() //> -1 ……Why?
num //> 3

xiaoyunyang

const getInfoFromURL = path => {
   const URL = require(“url”).URL;
   const myUrl = new URL(path)
   const pathname = myUrl.pathname
   
   const getUsernameFromURL = pathname => {
      const regex = new RegExp(‘/@’);
      const username = pathname.split(regex).slice(1)[0]
      if(!username) {
        return “Error in parsing: URL needs to be in format://hostname:port/@username”

xiaoyunyang

var multThenAdd = num => {
   return mul => add => {
      return num * mul + add
   }
}

var timesTwoPlusFour = (num) => multThenAdd(num)(2)(4)

timesTwoPlusFour(1) //> 6
timesTwoPlusFour(10) //> 24

xiaoyunyang

var incrementUntil = function(max) {
   var inc = function(num) { 
      if(num >= max) return num 
      return inc(num+1)
    }
    return (num) => inc(num)
}
	
incrementUntil(4)(1) //> 4
incrementUntil(8)(3) //> 8

xiaoyunyang

var myFun2 = function() { 
  var num = -1
  function incrementUntil(max) { 
     if(num >= max) return num 
     num++
     incrementUntil(max)
   }
   incrementUntil(3)
   return num 
}