marekdano

function debounce(callback, timer) {
  let timeoutId;

  return (...args) => {
    // save the current context (this)
    const context = this;

    // clear the existing timeout
    clearTimeout(timeoutId);

marekdano

const countries = [
  { value: 'AFG', name: 'Afghanistan' },
  { value: 'ALA', name: 'Aland Island' },
  { value: 'ALB', name: 'Albania' },
  { value: 'DZA', name: 'Algeria' },
  { value: 'ASM', name: 'American Samoa' },
  { value: 'AND', name: 'Andorra' },
  { value: 'AGO', name: 'Angola' },
  { value: 'AIA', name: 'Anguilla' },
  { value: 'ATG', name: 'Antigua and Barbuda' },

marekdano

// all credits for this gist goes to Bruno's video 
// https://www.youtube.com/watch?v=vXh4PFwZFGI

type DrawerProps = { fullName: string } & (
  | { shape: 'circle'; radius: number }
  | { shape: 'square'; width: number }
  | { shape: 'rectangle'; width: number; height: number }
);

<Drawer fullName="Marek Dano" shape="rectangle" width={5} height={4} />

marekdano

const factorial = num => (num > 1 ? num * factorial(num - 1) : 1)

const memoize = fn => {
  const cache = {}
 
  // with multiple arguments
  //   return (...args) => {
  //     const key = JSON.stringify(args)
  //     return key in cache ? cache[key] : cache[key] = fn.apply(null, args)
  //   }

marekdano

const curry = (fn) => {
	const curried = (...args) => {
		if (args.length >= fn.length) {
			return fn(...args)
		} else {
			return (...innerArgs) => curried(...args, ...innerArgs)
		}
	}
	return curried
} 

marekdano

const multiply = (a, b) => a * b

function prefillFunction (fn, prefilledValue) {
  const inner = liveInput => {
    const output = fn(liveInput, prefilledValue)
    return output
  }
  return inner
}

marekdano

function fail(arr: never): never {
  return new Error;
}

function pluck<T, K extends keyof T>(obj: T, propertyNames: K[]): T[K][] {
  return propertyNames.map(key => obj[key])
}

interface Author {
  name: string;

marekdano

import React, { useState, useRef, useEffect } from "react";
import { FontAwesomeIcon } from "@fortawesome/react-fontawesome";
import { faCheck } from "@fortawesome/free-solid-svg-icons";
import { library } from "@fortawesome/fontawesome-svg-core";

import "./styles.css";

library.add(faCheck);

/*

marekdano

// MAP
function map(array, callbackFunction) {
    var newArray = [];
    for (var i = 0; i < array.length; i++) {
        newArray[i] = callbackFunction(array[i]);
    }
    return newArray;
}

// Test

marekdano

// write function for fibonacci numbers where
// F[1]=F[2]=1; F[3]=2; F[4]=3; => 1,1,2,3,5,8,...
const fibRec = n => {
  if (n === 1 || n === 2) {
    return 1
  }
  return fibRec(n-1) + fibRec(n-2)
}

const fibImp = n => {