junaidtk

ES6 Features:

Classes.
Arrow functions.
Variable (let, var, const)
Array methods like .map().
Destructuring.
Modules.
Ternary Operator.
Spread Operator.

junaidtk

Temporal Dead Zone (TDZ) and Hoisting in JavaScript:

Temporal Dead Zone:
===================

Area of a block where the javascript variable is inaccessible untill the moment the computer completely intialised.

Block is a pair of braces used to group multiple braces.

Initialisation means: assigning a value to a variable.

junaidtk

WP-CLI
=======

WP-CLI is a command line interface for wordpress. You can install WP,  update plugin, install plugin, configure multisite and Much more without using web browser.

Download the wp-cli.phar file using wget or curl.

curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar

Then, check if it works:

junaidtk

When we need to transfer/import a repository into new repository without loosing the all the prior commits.

Then follow the below steps. 

1) Create a new repo with no any previous/initial commits like gitignore files or readme files. 
Because this will create conflict with existing repo file of old repository. 

2) Then clone the remote repo into a desired folder on your local system.

3) Checkout all the required remote branches in to the local branch. 

junaidtk

1) is_admin() check and AJAX Call
=================================
// Is admin, but not doing ajaax
if( is_admin() && ( ! defined( 'DOING_AJAX' ) || ! DOING_AJAX ) ) {
    require_once('admin/functions_admin.php'); 
}
// Is doing AJAX 
else if ( is_admin() && ( defined( 'DOING_AJAX' ) || DOING_AJAX ) ) {
    require_once('functions_ajax.php'); 
}

junaidtk

<?php 

$csv_data = generate_csv_file_data($from_date, $to_date);

header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private", false);
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"report.csv\";" );

junaidtk

Regular expression are patterns/combination of charactor used to match character, group of character or any combinations in a string.
$regular_expression = '';

Regular expression is pattern which is enclosed between slashes.
So our reqular expression become, 
$regular_expression = '//';

^ This will match the begining of a line.
$ will indicate the end of a line.
So $regular_expression become,

junaidtk

The eval is used to execute the a string value. If you want to execute a string value like 
an arithmetic string eg: "4+3*6", then you can use the eval function to calculate the string.

In php and javascript you can use the eval() function.
Javascript:
===========
The eval() function will leads to many syntax error whenever the statement inside the function is not executable.
So you can use the try{}catch{} method.

var statement = "4+3*6";

junaidtk

1)Get the last element of array:
===============================
let numbersArr = [4, 8, 9, 34, 100];
numbersArr[numbersArr.length - 1]; //return 100

2)Get a random number in a specific range:
=========================================
// Random number between 0 and 4.
Math.floor(Math.random() * 5);
// Random number between 0 and 49.

junaidtk

1)Using transform styling:
=====================
.child {
  position: relative;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
}