Various exercises from eloquentjavascript.net

exercises.js

// Chapter two - exercise one
// c2e1();
function c2e1() {
  var hashCount = 1;
  var hashes = '#';
  for (;hashCount <= 7; hashCount++) {
    console.log(hashes);
    hashes += '#';
  }
}

// Chapter two - exercise two
// c2e2();
function c2e2() {
  var n = 1;
  var output;
  
  for (;n <= 100; n++) {
    output = getWord(n);
    console.log(output);
  }
  
  function getWord(n) {
    var word = '';
    
    if (n % 3 === 0) word += 'Fizz';

    if (n % 5 === 0) word += 'Buzz';
    
    return word || n;
  }
 }

// Chapter two - exercise three
// c2e3();
function c2e3() {
  var grid = 8;
  var output = '\n';
  for (var i = 1; i <= grid; i++) {
    if (i % 2 === 0) {
      output += ' ';
    }
    
    for (var j = 1; j <= grid; j++) {
      if (j % 2 === 0) {
        output += ' ';
      } else {
        output += '#';
      }
    }
    output += '\n';
  }
  
  console.log(output);
}

// Chapter three - exercise one
// c3e1();
function c3e1() {
  function min(a, b) {
    if (a <= b) return a;
    return b;
  }
  
  console.log(min(8, 6));
}

// Chapter three - exercise two
// c3e2();
function c3e2() {
  function isEven(n) {
    if(n === 0) {
      return true;
    } else if(n === 1) {
      return false;
    } else if(n < 0) {
      return isEven(-n);
    } else {
      return isEven(n - 2)
    }   
  }
  
  console.log(isEven(3));
  console.log(isEven(86));
  console.log(isEven(-43));
}

/**
 * Chapter three - exercise three
 */
c3e3();
function c3e3() {
  function countChars(haystack, needle) {
    var wordLength = haystack.length;
    var counter = 0;
    
    for(var i = 0; i < wordLength; i++ ) {
      if (haystack.charAt(i) === needle) { 
        counter++
      }
    }
    
    return counter;
  }
  
  function countBs(word) {
    return countChars(word, 'B');
  }
  
  console.log(countBs('hello there BiBi'));
  console.log(countChars('All of the a\'s are here', 'a'));
}


/**
 * Chapter four - exercise one
 */
//c4e1();
function c4e1() {
  function flatten(arr) {
    return arr.reduce(function(flatten, current) {
      return flatten.concat(current);
    }, []);
  }
  
  console.log(flatten([[1, 2], [4, 5]]));
}