SK-CSE

/*
 * Inspired by: http://stackoverflow.com/questions/4360060/video-streaming-with-html-5-via-node-js
 */

var http = require('http'),
    fs = require('fs'),
    util = require('util');

http.createServer(function (req, res) {
  var path = 'video.mp4';

SK-CSE

// factorial
function factorial(number) {
   var product = 1;
   for (var i = 1; i <= number; i++) {
      product *= i;
   }
   return product;
}

// factorial recursive

SK-CSE

// with prototype
function BankAccount(amount) {
   this.balance = amount;
}

BankAccount.prototype.deposit = function(amount) {
   this.balance += amount;
}

BankAccount.prototype.withdraw = function(amount) {

SK-CSE

function firstLetter(word) {
   return word[0];
};

function getAcronym(str){
  var words = str.split(" "); // ["for","your","information"]
  var acr = words.map(firstLetter); // ["f","y","i"]
  return acr.join("").toUpperCase();
};

SK-CSE

function isEven(num) {
   return num % 2 == 0;
}
function isOdd(num) {
   return num % 2 != 0;
}
var nums = [];
for (var i = 0; i < 20; ++i) {
   nums[i] = i+1;
}

SK-CSE

// The mutator function for adding array elements to the beginning of an array is unshift(). Here is how the function works:
var nums = [2,3,4,5];
console.log(nums); // 2,3,4,5
var newnum = 1;
nums.unshift(newnum);
console.log(nums); // 1,2,3,4,5

// The second call to unshift() demonstrates that you can add multiple elements to an array with one call to the function.
nums = [3,4,5];
nums.unshift(newnum,1,2);

SK-CSE

// JavaScript arrays are only one-dimensional, but you can create multidimensional arrays by creating arrays of arrays.
Array.matrix = function(numrows, numcols, initial) {
   var arr = [];
   for (var i = 0; i < numrows; ++i) {
      var columns = [];
      for (var j = 0; j < numcols; ++j) {
         columns[j] = initial;
      }
      arr[i] = columns;
   }

SK-CSE

###JavaScript's && operator is coalescing.

js> 0 && 7
0
js> 1 && 7
7

&& does not convert things to Boolean values.

SK-CSE

+ operator in string and number

var a = "3"+1+2;
console.log(a); //312

var b = 1+"3"+2;
console.log(b); //132

var c = 1+2+"3";
console.log(c); //33

SK-CSE

JSON Stringification

For most simple values, JSON stringification behaves basically the same as toString() conversions, except that the serialization result is always a string:

JSON.stringify( 42 );	// "42"
JSON.stringify( "42" );	// ""42"" (a string with a quoted string value in it)
JSON.stringify( null );	// "null"
JSON.stringify( true );	// "true"

The JSON.stringify(..) utility will automatically omit undefined, function, and symbol values when it comes across them. If such a value is found in an array, that value is replaced by null (so that the array position information isn't altered). If found as a property of an object, that property will simply be excluded.