Solutions to the exercises from Chapter 2 of Eloquent JavaScript.

eloquent-javascript-exercises-ch2.js

'use strict'

// Looping a Triangle
// Write a loop that makes seven calls to console.log to output the following triangle:

// #
// ##
// ###
// ####
// #####
// ######
// #######
 
for (let outputCharacter = '#'; outputCharacter.length < 8; outputCharacter += '#') {
    console.log(outputCharacter);
}

// FizzBuzz
// Write a program that uses console.log to print all the numbers from 1 to 100, with two exceptions. For numbers divisible by 3, print "Fizz" instead of the number, and for numbers divisible by 5 (and not 3), print "Buzz" instead.

// When you have that working, modify your program to print "FizzBuzz", for numbers that are divisible by both 3 and 5 (and still print "Fizz" or "Buzz" for numbers divisible by only one of those).

for (let number = 1; number < 101; number++) {
    let text = '';
    
    let isDivisibleBy3 = number % 3 === 0;
    let isDivisibleBy5 = number % 5 === 0;
    
    if (isDivisibleBy3)
        text += 'Fizz';
    if (isDivisibleBy5)
        text += 'Buzz';
        
    console.log(text || number); // outputs a Fizz/Buzz/FizzBuzz string, or if text is empty, outputs the number
}

// Chess board
// Write a program that creates a string that represents an 8×8 grid, using newline characters to separate lines. At each position of the grid there is either a space or a “#” character. The characters should form a chess board.

// Passing this string to console.log should show something like this:

//  # # # #
// # # # #
//  # # # #
// # # # #
//  # # # #
// # # # #
//  # # # #
// # # # #
// When you have a program that generates this pattern, define a variable size = 8 and change the program so that it works for any size, outputting a grid of the given width and height.

const size = 8;  // this can be changed to any size grid

let string = '';

for (let i = 0; i < size; i++) {
    for (let j = 0; j <= size; j ++) {
        
        if (j === size) {
            string += '\n';
            break;
        }
        
        let character = i + j; // toggles the output character on even/odd lines
        if (character % 2 === 0) 
            string += ' ';
        else 
            string += '#';
    }
}

console.log(string);