Map

The map() method is used for creating a new array from an existing one, applying a function to each one of the elements of the first array.

let numbers = [1, 2, 3, 4, 5];
let doubled = numbers.map(num => num * 2);
console.log(doubled) // [2, 4, 6, 8, 5] 

Filter

The filter() method takes each element in an array and it applies a conditional statement against it. If this conditional returns true, the element gets pushed to the output array. If the condition returns false, the element does not get pushed to the output array.

const numbers = [1, 2, 3, 4];
const odds = numbers.filter(num => num % 2 === 1);
console.log(odds); // [1, 3]

Or with an array of Objects you can implement filter() like the following.  

const students = [
   {name: 'eric', age: 12},
   {name: 'Jenny' age: 11},
   {name: 'Freddy', age: 9}
];
const overTen = students.filter(student => student.age > 10);
console.log(overTen); // [{name:'Eric', age:12}, {name:'Jenny', age:11}]

Reduce

The reduce() method reduces/calculates a value down to a single value. To get the output value, it runs a reducer function on each element of the array.

const array1 = [1, 2, 3, 4];   // 0 + 1 + 2 + 3 + 4
const initialValue = 10;
const sumWithInitial = array1.reduce(
(accumulator, currentValue) => accumulator + (currentValue * 10), 
initialValue);

// Expected output is 110.  Ok so the accumulator starts at the value of zero.  And then accumulator is accumulator plus currentValue times 10.  Add 10(initialValue... we set it to 10) + 10 + 20 + 30 + 40

What is the __invoke() method used for in objects?  The __invoke() method is a PHP magic method that allows an object to be called as if it were a function.  It’s great for maintaining state and focusing on a single calculation.

Let’s take a look a more practical use.  In this example we will use it for issuing API requests:

 class HttpRequest {

    public function __construct(private string $url)

    {   

    }

    public function __invoke($data) {

        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, $this->url);

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        $response = curl_exec($ch);

        curl_close($ch);

        return $response;

    }

 }

 $amazon = new HttpRequest('https://api.example.com/amazon/store');

 $temu = new HttpRequest('https://api.example.com/temu/store');

 $amazonResponse = $amazon(['item_id'=>12333]);

 $temuResponse = $amazon(['item_id'=>12333]);

Overview of the Switch Statement

  The switch statement is a control structure available in almost every programming and scripting language.  It allows the developer to execute different blocks of code based on the value of an expression.  It is often used as a cleaner alternative to multiple if-else statements.  You may be asking yourself why use the switch statement since we already have if-else.  

   There are differences though.  And depending on the task-at-hand, the switch statement can be a better alternative than if-else.  

Structure:

 switch (expression) {

    case value1:

        // execute this code block only

        break;

    case value2:

        // execute this code block only

        break;

    default:

        // execute if no cases match

 }

   A switch statement evaluates an expression and executes the code block for the first case that matches its value.

   The break keyword is crucial. When encountered, it exits the entire switch statement immediately. Without it, execution will "fall through" and run the code in the subsequent case, even if the value doesn't match.  If no matching case is found, the optional default block is executed.

Example:

 let day = 'Monday';

 let output = '';

 switch (day) {

    case 'Monday':

        output = `Day is Monday`;

    case 'Tuesday':

        output = `Day is Tuesday`;

        break;

    case 'Wednesday':

        output = `Day is Wednesday`;

        break;

    case 'Thursday':

        output = `Day is Thursday`;

        break;

    case 'Friday':

        output = `Day is Friday`;

        break;

    case 'Saturday':

        output = `Day is Saturday`;

        break;

    case 'Sunday':

        output = `Day is Sunday`;

        break;

    default:

        output = `No day specified`;

 }

 // Output if day == 'Monday' OR day == 'Tuesday':

 // Day is Tuesday

 // Output if day == 'Saturday':

 // Day is Saturday

 // Output if day == 'Nothing'

 // No day specified

   This example demonstrates a crucial concept in JavaScript's switch statement: fallthrough.  When day is 'Monday', the output will indeed be "Day is Tuesday".  Here’s why: The switch statement finds a match on case 'Monday' and begins executing the code on the next line, setting output = 'Day is Monday'.

  Because there is no break keyword at the end of the 'Monday' case, the logic "falls through" and continues to execute the very next line of code, which is the start of the 'Tuesday' case.  It then executes output = 'Day is Tuesday', overwriting the previous value.  Finally, the break keyword at the end of the 'Tuesday' case is encountered, which halts the execution of the switch block entirely.

   The break statement is not optional for most use cases. It is essential for exiting the switch block once a specific case's code has finished running. Without it, execution will continue into the next case, whether it matches or not.

   The default case is only executed if no other case values match the expression. It will not be executed simply because of a fallthrough from a matched case (unless that fallthrough leads all the way to it).

Spread Operator (...)

The PHP Spread Operator (...) is a powerful feature introduced in PHP 5.6 that allows you to "unpack" or "spread" elements from arrays and traversable objects. It's also known as the splat operator or unpacking operator.

The spread operator is particularly useful in modern PHP development for creating more expressive and efficient code when working with arrays and variable function arguments.

Key Benefits of the PHP Spread Operator

1. Cleaner syntax for array merging and function calls

2. Better performance in some cases compared to array_merge()

3. More readable code when dealing with multiple arrays

4. Flexible for both array operations and function arguments
   
   
   

Here are a few common use cases for the operator:

Unpack and Merge Multiple Arrays

Here are a couple of examples for unpacking and merging arrays.  

 $array1 = [1, 2, 3];

 $array2 = [4, 5, 6];

 $array3 = [7, 8, 9];

 $merged = [...$array1, ...$array2, ...$array3];

 // Array (

 //  [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5

 //  [5] => 6 [6] => 7 [7] => 8 [8] => 9

 // )

 $original = ['b', 'c', 'd'];

 $newArray = ['a', ...$original, 'e'];

 // Array (

 //   [0] => a [1] => b [2] => c [3] => d [4] => e

 // )

Function Arguments

 // FUNCTION ARGUMENTS

 function addNumbers($a, $b, $c) {

    return $a + $b + $c;

 }

 $numbers = [2, 4, 6];

 $result = addNumbers(...$numbers);

 echo $result; // Output: 12

 function sum(...$numbers) {

    return array_sum($numbers);

 }

 $values = [1, 2, 3, 4, 5];

 echo sum(...$values); // Output: 15

Combining With Regular Elements

 // Combining with Regular Elements

 $first = [1, 2];

 $last = [5, 6];

 $combined = [...$first, 3, 4, ...$last];

 print_r($combined);

 // Output: Array ([0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6)

Usage With Associative Arrays

Notice that array keys are also considered making it perfect for merging associative arrays as well.  

 //With Associative Arrays

 $config1 = ['host' => 'localhost', 'port' => 3306];

 $config2 = ['username' => 'root', 'password' => 'secret'];

 $finalConfig = [...$config1, ...$config2];

 print_r($finalConfig);

// Output: Array ([host] => localhost [port] => 3306 [username] => root [password] => secret)

String To Array Conversion

 // String To Array Conversion

 $string = "hello";

 $chars = [...$string];

 print_r($chars);

 // Output: Array ([0] => h [1] => e [2] => l [3] => l [4] => o)

Practical Example of Merging 2 Configuration Arrays

Remember that when merging 2 associative arrays using the spread operator and brackets syntax, the second array in the will overwrite values with matching keys.  Take a look at the ‘debug’ key below:

 // Configuration Merging

 $defaultConfig = [

    'debug' => false,

    'cache' => true,

    'timeout' => 30

 ];

 $userConfig = [

    'debug' => true,

    'database' => 'mysql'

 ];

 $finalConfig = [...$defaultConfig, ...$userConfig];

 print_r($finalConfig);

 // Output: Array ([debug] => true [cache] => true [timeout] => 30 [database] => mysql)

This tutorial The JavaScript Date library is a built-in object that represents a single moment in time. It provides methods for creating, parsing, formatting, and manipulating dates and times. Dates are stored as the number of milliseconds since the Unix epoch (January 1, 1970, 00:00:00 UTC).

In this tutorial I will cover how to format date only, time only, and both date and time using these 3 methods from built-in object Date. A method to format a date. A method to format a time. And a method to format both date and time.  

const date = new Date('2025-10-23 11:06:48');

date.toLocaleDateString('en-US');

date.toLocaleTimeString('en-US');

date.toLocaleString('en-US');

Also, I have included 2 handy references at the end of this tutorial.  A reference for options and values available to define the format.  Also, a reference that lists all available methods on the Javascript built-in Date object. 

Date toLocaleDateString()

The toLocaleDateString() method formats the date only.  Below the value of the date will be initiated as datetime (yyyy-mm-dd hh:mm:ss):

const date = new Date('2025-10-23 11:06:48');

Even though the Date object is initiated with a date and time string, only the date part of the string will be extracted. The default date.toLocaleDateString('en-US') returns the date formatted as mm/dd/yyyy.  Also use other formatting options available. The options are referenced below. 

 const date = new Date('2025-10-23 11:06:48');

 // Date only

 date.toLocaleDateString('en-US');

 // "10/23/2025"

 date.toLocaleDateString('en-US', {

   year: 'numeric',

   month: 'long',

   day: 'numeric'

 });

 // "October 23, 2025"

Date toLocaleTimeString()

Target and format the time portion of the string using toLocaleTimeString().  Now time is extracted from the initial value set below…  

 const date = new Date('2025-10-23 11:06:48');

The toLocaleTimeString() method can be used with or without options. The default time is in 12 hour format (hh:mm:ss AM/PM).  Options are listed below:

 // Time only

 date.toLocaleTimeString('en-US');

 // "11:06:48 AM"

 date.toLocaleTimeString('en-US', {

    hour: '2-digit',

    minute: '2-digit',

    hour12: true

 });

 // "11:06 AM"

Date toLocaleString()

To format both the date and time use toLocaleString().  This method also accepts options to provide formatting instructions.  Refer to the list below.  

 // Combined date and time

 date.toLocaleString('en-US');

 // "10/23/2025, 11:06:48 AM"

 date.toLocaleString('en-US').replace(/,/g, '');

 // "10/23/2025 11:06:48 AM"

Below are all the possible format options that can be passed to toLocaleString() for the en-US locale.

Option Reference Table toLocaleString() 

JavaScript Date Library Function Reference

Constructor Methods

Static Methods

Getter Methods: Local Time Getters

UTC Getters

Setter Methods

Local Time Setters

UTC Setters

Conversion Methods

Value Methods

This tutorial guides you through backing up MySQL and PostgreSQL databases from the command line. While their native tools—mysqldump and pg_dump—share a similar purpose, their command syntax differs. We will cover the essential commands for both systems, highlighting their key similarities and differences. 

Backup MySQL / MariaDB Database

Export every table’s schema and existing records to an SQL executable script.

mysqldump -u username -p database_name > database.sql

This will export the specified table’s schema and records to an executable script.

 mysqldump -u username -p database_name table_name > db_table.sql

This will export the specified table’s data only(no schema).

 
mysqldump -u username -p --no-create-info database_name table_name > table_data.sql

This will export the specified table’s schema only(no data).

mysqldump -u username -p --no-data database_name table_name > table_schema.sql

Restore MySQL / MariaDB Database

 mysql -u username -p database_name < database.sql

Backup PostgreSQL Database

Export every table’s schema and existing records to an SQL executable script.

 pg_dump -U username database_name > database.sql

This will export both the specified table’s schema and data to an executable script.

 pg_dump -U username -t table_name database_name > table.sql

Only data (no schema):

 pg_dump -U username -a -t table_name database_name > table_data.sql

Only schema (no data):

 pg_dump -U username -s -t table_name database_name > table_schema.sql

Restore PostgreSQL Database

 psql -U username -d database_name -f database.sql