simple exercise

js-browser.js

// Grade conversion
sistemaNotas = function(nota){
    if(nota>100||nota<1) return 'Invalid score';
    if(nota<60){
        return 'F'
    } else if(nota<70) {
        return 'D'
    } else if(nota<80) {
        return 'C'
    } else if(nota<90) {
        return 'B'
    } else if(nota>=90) {
        return 'A'
    }
}


// Finances
let wallet = {
	income: [],
	outcome: []
}

fillWallet = function(){
    for(let i = 0; i<10;i++){
						wallet.income.push(Math.floor(Math.random()*1000)/100)
wallet.outcome.push(Math.floor(Math.random()*1000)/100)
	}
}

processBalance = function(){
    let position = 0;
    for(let income of wallet.income){
        position += income  
    }
    for(let outcome of wallet.outcome){
        position -= outcome 
    }
    console.log(`Your balance is ${position} and ${(position>0)?'it is positive.':'you should get back to work.'}`)
}
//fillWallet();
//processBalance();


//C to F and F to C - with c or f in the 'temperature' string
convertCtoFandFtoC = function(temperature =''){
    if(temperature.toLowerCase().includes('c')){
        const value = temperature.toLowerCase().split('c')[0];
        return (value * 9/5 + 32)
    }
    if(temperature.toLowerCase().includes('f')){
        const value = temperature.toLowerCase().split('f')[0];
        return ((value-32) * 5/9)
    }
}

//
// Books by category
const booksByCategory = [
  {
    category: "Riqueza",
    books: [
      {
        title: "Os segredos da mente milionária",
        author: "T. Harv eker"
      },
      {
        title: "O homem mais rico da Babilônia",
        author: "George S. Clason"
      },
      {
        title: "Pai rico, pai pobre",
        author: "Robert T. Kiyosaki e Sharon L. Lechter"
      },
    ]
  },
  {
    category: "Inteligência Emocional",
    books: [
      {
        title: "Você é Insubstituível",
        author: "Augusto Cury"
      },
      {
        title: "Ansiedade - Como enfrentar o mal do século",
        author: "Augusto Cury"
      },
      {
        title: "7 hábitos das pessoas altamente eficazes",
        author: "Stephen R. Covey"
      },
    ]
  }
]

processBooksByCategory = function(authorName) {
  let totalCategories = 0;
  let totalBooks = 0;
  let totalAuthors = 0;
  let totalBooksFromAuthor = 0;
  booksByCategory.forEach(cat => {
    totalCategories++;
    cat.books.forEach(() => {
      totalBooks++;
    });
    // count authors
    let authors = cat.books.reduce((acc, value) =>
      (acc.indexOf(value.author) == -1) ? acc.concat(value.author) : acc, []);
    totalAuthors += authors.length;
    totalBooksFromAuthor += cat.books.reduce((acc, book) =>
      (book.author === authorName ? acc + 1 : acc), 0);
  });
  console.log(`You have ${totalCategories} categories, ${totalBooks} books total and ${totalAuthors} authors.`);
  if (authorName) {
    console.log(`Your author ${authorName} has, ${totalBooksFromAuthor} books registered.`);
  }
}