intro-js/js_exercises.html at master · a17w/intro-js · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <title>Javascript Example</title>
  </head>
  <body>

    <script>
      // JAVASCRIPT INTRO!!
      // RUBY CONSOLE:
      // puts "hello"


      // JS CONSOLE:
      // console.log("hello");


      // RUBY PROMPT:
      // puts "What is your name?"
      // username = gets.chomp


      // JS PROMPT:
      // var username = prompt("What is your name?");
      // console.log(username);


      // RUBY VARIABLES:
      // x = "hello"
      // puts x


      // JS VARIABLES
      // var x = "hello";
      // console.log(x);


      // RUBY CONCAT:
      // x = "cat"
      // y = "dog"
      // puts "#{x}#{y}"


      // JS CONCAT:
      // var x = "cat";
      // var y = "dog";
      // console.log(x + y);


      // RUBY NUMS:
      // x = 1
      // y = 2
      // z = 4.34
      // puts x + y
      // puts x + z


      // JS NUMS:
      // var x = 1;
      // var y = 2;
      // var z = 4.34;
      // console.log(x+y);
      // console.log(x + z);


      // RUBY INC/DEC:
      // x = 1
      // x += 1
      // x -= 1


      // JS INC/DEC:
      // var x = 2;
      // x++;
      // console.log(x);
      // x--;
      // console.log(x);


      // RUBY BOOLS:
      // x = true
      // y = false
      // puts x
      // puts y


      // JS BOOLS:
      // var x = true;
      // var y = false;
      // console.log(x, y);


      // RUBY ARRAYS:
      // people = ["Wen", "Dani", "Annie"]
      // puts people[0]
      // puts people[1]
      // people << "Jenilee"
      // puts people
      // puts people.count


      // JS ARRAYS:
      // var people = ["Wen", "Dani", "Annie"];
      // console.log(people[0]);
      // console.log(people[1]);
      // people.push("Jenilee");
      // console.log(people.length);


      // // INDEX OF ELEMENT IN ARRAY JS:
      // console.log(people.indexOf("Wen"));


      // RUBY HASHES
      // person = {first_name: "John", last_name: "Doe", eye_color: "Brown", age: 40}
      // puts person[:first_name]
      // x = :first_name
      //puts person[x]


      // JS OBJECTS:
      // var person = {first_name: "John", last_name: "Doe", eye_color: "Brown", age: 40};
      // console.log(person.first_name);
      // console.log(person['first_name']);
      // var x = "first_name";
      // console.log(person[x]);
      // console.log(person.x); DOESN'T WORK!


      // RUBY UNDEFINED:
      // x
      // puts x


      // JS UNDEFINED:
      // var x;
      // console.log(x);


      // RUBY TYPE:
      // puts "Wen".class => String
      // puts 1.class => Integer
      // puts 1.23.class => Float
      // puts false.class => FalseClass
      // puts {name: "wen"}.class => Hash


      // JS TYPE:
      // console.log(typeof "Wen"); // string
      // console.log(typeof 2.15); // number
      // console.log(typeof false); //boolean
      // console.log(typeof [1,2,3]); //object
      // console.log(typeof {name: "wen"}); //object


      // RUBY TYPE CONVERSION:
      // "234".to_i
      // 234.to_s


      // JS TYPE CONVERSION:
      // console.log(parseInt("234"));
      // var num = 234;
      // console.log(num.toString());


      // Exercise
      //create an array of three “pets” and output the second pet to the console.
      var pets = ["dog", "fish", "cat"];
      console.log(pets[1]);

      // add a 4th pet on a new line without changing the code of your original array.
      pets.push("hamster");
      console.log(pets);

      // With your pets array you’ve just created, how can you get returned the index position of the last pet you added?
      console.log(pets.indexOf("hamster"));

      //what gets returned if you search for the index of a pet that isn’t in your pets array?
      console.log(pets.indexOf("chicken"));
      //returns -1

      //Create an object that represents a particular book, having properties of title, author, isbn, pages, and year of publication. Now turn “book” into an array of “books” (add a second book).
      var books = [{
        title: "The Girl on the Train",
        author: "Paula Hawkins",
        isbn: "9781594634024",
        pages: "336",
        year: "2016"
      },
      {
        title: "Be Before You",
        author: "Jojo Moyes",
        isbn: "9780143130154",
        pages: "480",
        year: "2012"
      }];

 // Add a 3rd book a new line without changing your code of “books”.
      var newbook = {
        title: "Gone Girl",
        author: "Gillian Flynn",
        isbn: "9780307588371",
        pages: "432",
        year: "2014"
      };

      books.push(newbook);
      console.log(books);

    </script>

  </body>
</html>