functions_1.js

//  Part I

/**
 * use any of the looping methods discussed in class
 *
 * 1. for loop,
 * 2. Array.forEach,
 * 3. custom forEach
 *
 * to complete the following problems
 */

// 0. write your own forEach() that takes two arguments: an array, and a callback

function forEach(array, callback){
    for (var i = 0; i < array.length; i++) {
       callback(array[i]); 
    };
}

// testing your code with console.assert
var total = 1;
forEach([1, 2, 3, 4], function(a){ total *= a; });
// and finally assert; if this fails, the program stops
console.assert(total === 24);


// 1. calculate the sum of numbers (returns the sum (A NUMBER))

function sum(){
    // parse arguments into an array
    var args = [].slice.call(arguments);
    var total = 0; 
    forEach(args, function(a){ total += a; });
    return total;
}

console.assert( sum(1, 2, 3, 4, 5) === 15 )

// 2. calculate the average of numbers (returns the average (A NUMBER))

function average(){
    // parse arguments into an array
    var args = [].slice.call(arguments);
    var total = 0;
    forEach(args, function(a){ total += a; });
    return total / args.length;
}

console.assert( average(2, 4, 6, 8) === 5 )

// 3. find the largest number of the inputs (returns the largest input (A NUMBER))

function largest(){
    // parse arguments into an array
    var args = [].slice.call(arguments);
    var l = 0;
    forEach(args, function(a){
        if (a > l) { l = a; };
    });
    return l;
}

console.assert( largest(2, 4, 6, 8) === 8 )

// 4. find the longest string of the inputs (returns the longest input (A STRING))

function longest(){
    // parse arguments into an array
    var args = [].slice.call(arguments);
    var l = "";
    forEach(args, function(a){
        if (a.length > l.length) { l = a; };
    });
    return l;
}

console.assert( longest("shelby", "boss", "mach1", "rousche") === "rousche" )

// 5. write a function that can sort an array of Date objects (returns a NEW ARRAY of Date's)

function sort(){
    // parse arguments into an array
    var args = [].slice.call(arguments);
    return args.sort(function(a,b) {
        return a > b; 
    })
}

var dates = [
    new Date("Oct 2, 2015"),
    new Date("Oct 1, 2015"),
    new Date("Jan 2, 2015"),
    new Date("Dec 5, 2014"),
    new Date("Mar 27, 2015")
]

var sorted = sort(dates[0], dates[1], dates[2], dates[3], dates[4]);

console.assert(
    sorted[0] === dates[3] &&
    sorted[1] === dates[2] &&
    sorted[2] === dates[4] &&
    sorted[3] === dates[1] &&
    sorted[4] === dates[0]
)

/**
 * PART II
 *
 * For each of the following Array methods,
 *
 * 1. use them in an example
 * 2. write a console.assert to test them
 */

// .sort()
var grades = [89, 50, 94, 83];
var sorted = grades.sort(function(a, b) { return a - b });

console.assert(
    grades[0] === 50 &&
    grades[1] === 83 &&
    grades[2] === 89 &&
    grades[3] === 94
)

// .concat()
var first = "This is the first part ";
var second = "and this would be the second part.";
var phrase = first.concat(second);

//console.log(phrase)

console.assert(
    phrase === "This is the first part and this would be the second part."
)
// .indexOf()
var bit = "Tomorrow will be Wednesday.";
var bat = bit.indexOf("w");
//console.log(bat)

console.assert(
    bat === 7
)

// .split()
var john = "We are";
var jim = john.split(" ");
//console.log(jim);

console.assert(
    jim[0] === 'We' &&
    jim[1] === 'are' 
)


// .join()
var students = ["Mary", "Larry", "Harry"];
var group = students.join();
//console.log(group);

console.assert(
    group === 'Mary,Larry,Harry'
)

// .pop()
var cards = ["Ace", "King", "Queen", "Jack"];
var draw = cards.pop();
//console.log(draw);

console.assert(
    draw === "Jack"
)

// .push()
var food = ["breakfast", "lunch"];
var night = food.push("dinner");
//console.log(night);

console.assert(
    night === 3
)
// .slice()
var states = ["Georgia", "Florida", "Ohio", "Alaska"];
var south = states.slice(0,2);
//console.log(south);

console.assert(
    south[0] === 'Georgia' &&
    south[1] === 'Florida'
)


// .splice()
var tv = ["Family Ties", "Seinfeld", "Night Court", "Cheers"];
var eighties = tv.splice(1, 2);

//console.log(eighties);

console.assert(
    eighties[0] === "Seinfeld" &&
    eighties[1] === "Night Court" 
)


// .shift()
var cabinet = ["cereal", "pasta", "snacks",];
var pat = cabinet.shift();

//console.log(pat)

console.assert(
    pat === 'cereal'
)
// .unshift()
var hip = [1, 2, 3, 4];
var hap = hip.unshift(5, 6);

//console.log(hap);

console.assert(
    hap === 6
)



// .filter()

var yip = [1, 2, 3, 4];
var yap = yip.filter(function(x) { return x < 3 });
//console.log(yap);

console.assert(
    yap[0] === 1 &&
    yap[1] === 2
)

// .map()

var wer = ["a", "b", "c"];
var war = wer.map(function (x) {return x.toUpperCase()});

//console.log(war);

console.assert(
    war[0] === "A" &&
    war[1] === "B" &&
    war[2] === "C"
)

/**
 * PART III
 *
 * Fill in the sections below marked 'YOUR CODE HERE'.
 *
 * The code below should find all customers whose first-names start with 'J',
 * map() those people into an array of objects that have a name property:
 *
 * i.e. { name : c.firstname + " " + c.lastname }
 *
 * then sort them alphabetically
 */

// set up arrays
var numbers = [1, 12, 4, 18, 9, 7, 11, 3, 101, 5, 6];
var strings = ['this', 'is', 'a', 'collection', 'of', 'words'];

var customers = [{
    firstname: 'Joe',
    lastname: 'Blogs'
}, {
    firstname: 'John',
    lastname: 'Smith'
}, {
    firstname: 'Dave',
    lastname: 'Jones'
}, {
    firstname: 'Jack',
    lastname: 'White'
}];

console.log(customers);

var projections = customers
.filter(function(c) { return c.firstname.indexOf('J') == 0
})
.map(function(c) {return { name : c.firstname + " " + c.lastname
}
})
.sort(sortByName);

function sortByName(c1, c2) {
    "use strict";
}

console.log(projections);