srsandy

PROTOTYPE IN JS. 😄

By default every function has a property name as prototype which is EMPTY (by default). We can add properties and methods to it.

Note: Every function is a contructor function in JS.

Let's say we have an function x and create an object x of x as x1 will inherite the prototype of x.

srsandy

EventEmitter() in NodeJS 😄

EventEmitter is a class in NodeJS that helps to listen or fire events in your application. You can also keep track of events in you application.

Let's start with a simple eventEmitter example. First of all we need to add Event Object in our project

const events = require('events');
var eventEmitter = new events.EventEmitter();

srsandy

Strings

String.prototype.*

None of the string methods modify this – they always return fresh strings.

• charAt(pos: number): string ^ES1

  Returns the character at index pos, as a string (JavaScript does not have a datatype for characters). str[i] is equivalent to str.charAt(i) and more concise (caveat: may not work on old engines).

srsandy

Javascript Notes

var, let & const

• var provides functional scoping but not block scoping. var allow to log the variable without declaring it though it shows undefined.
• let provides functional scoping as well as block scoping.
• const provies functional scoping as well as block scoping but you cannot reassign value to a const type variable.

let and const will not allow you the log the variable without declaring it.

| Keyword | Scope | Hoisting|Can Be Reassigned|Can Be Redeclared

srsandy

IE6 Only
==================
_selector {...}

IE6 & IE7
==================
*html or { _property: }

IE7 Only
==================

srsandy

// write.c
#include<stdio.h>
#include <sys/ipc.h> 
#include <sys/shm.h> 
#include <stdio.h>

int main(int argc, char const *argv[]) {
	int key = ftok(".", 34);
	int *arr;
	

srsandy

public String Add(String input1, String input2) {  
	String ans = "";
	int len1 = input1.length();
	int len2 = input2.length();

	if(len1 < len2){
		String temp = input1; 
		input1 = input2; 
		input2 = temp; 
	}

srsandy

Methods that can help you code quicker and better.

String/Array

toCharArray() //get char array of a String

charAt(int x) //get a char at the specific index

length() //string length

srsandy

srsandy

Array Sorting Algorithms Complexity

Name	Best	Average	Worst	Memory	Stable	Comments
Bubble sort	n	n2	n2	1	Yes
Insertion sort	n	n2	n2	1	Yes
Selection sort	n2	n2	n2	1	No
Heap sort	n log(n)	n log(n)	n log(n)	1	No
Merge sort	n log(n)	n log(n)	n log(n)	n	Yes
Quick sort	n log(n)	n log(n)	n2	log(n)	No	Quick