jonasantonelli

import {assert} from 'chai';

export namespace Dictionaries {
    
    /**
      * Create a deep copy of a dictionary such that all of the origina keys are maintained 
      * and copied into a new dictionary. 
      * 
      * This is used when we have to create a copy of a dictionary to prevent concurrent mutation 
      * or when we need to copy it and then make changes to the new dictionary.

jonasantonelli

import {assert} from 'chai';

/**
 * Implement a class named ring buffer with fixed capacity such that
 * 
 * constructor: takes the capacity for the ring buffer
 *
 * push: adds a value to the ring buffer.
 * pop: removes the last value from the ring buffer or undefined if it's empty.
 * peek: returns the current value of the most recent value added or undefined if none have been added

jonasantonelli

import React from 'react';

/**
 * Implement a replacement for useState which keeps values in the localStorage.
 *
 * The idea here is that all calls to use useState can be replaced with
 * useLocalStorageState(key, initialValue) and implement the same behavior.
 *
 * The first time useLocalStorageState is called the value will be initialValue 
 * because nothing is stored in localStorage.

jonasantonelli

import styled, { css } from 'styled-components';

/*
* Switching <ul> element to <ol> and styling  
*/
const UnorderedList = styled.ul`
  list-style: circle;
  li {
    text-transform: uppercase;
    margin-bottom: 8px;

jonasantonelli

import styled, { css } from 'styled-components';

/*
* Switching <ul> element to <ol>  
*/
const UnorderedList = styled.ul`
  list-style: circle;

  li {
    text-transform: uppercase;

jonasantonelli

import styled from 'styled-components'

const Item = styled.li`
  color: cadetblue;
`;

const UnorderedList = styled.ul`
  list-style: none;

  ${Item} {

jonasantonelli

// Function composition is a way to combine several simpler function into a more complicated one.

const readFromTextInput = (): string => {
  // some pseudocode
  return "abcde"
}

const addSignature = (input: string): string => {
  return input + 'Hello AI.';
}

jonasantonelli

/**
 *
 * @param {string} variable (--variable)
 * @param {HTMLElement} element (document.documentElement)
 * @param {string} pseudoElt (:after)
 */
function getCssVariable(variable, element = document.documentElement, pseudoElt) {
  const isValid = /--[\S]*/g;
  let propertyValue = '';

jonasantonelli

import React from 'react';
import ReactDOM from 'react-dom';
import UnorderedList from './UnorderedList';

const App = () => (
  <UnorderedList>
    <li>Item X</li>
    <li>Item Y</li>
  </UnorderedList>
);

jonasantonelli

import styled, { css } from 'styled-components';

/**
* Extending from another component
*/
const List = styled.ul`
  list-style: auto;

  li {
    text-transform: uppercase;