"I am Saqib Jahangir. A passionate vlogger, software engineer, trainer and avid traveler with a deep love for exploring the hidden gems of our beautiful planet. With a strong foundation in Application Development, Application Architecture & Database Design and Product Management, I bring over a decade of hands-on experience building secure, scalable, and resilient web applications for a diverse range of industries."

JavaScript Loops and Iterators (Advanced)

 

Beyond basic for and while loops, JavaScript provides advanced iteration methods and special loops for working with objects and arrays more efficiently.

1. for...in Loop

for...in is used to loop over the properties of an object.

let person = { name: "Alice", age: 25, city: "Dubai" };
 
for (let key in person) {
  console.log(key + ": " + person[key]);
}
// Output:
// name: Alice
// age: 25
// city: Dubai

⚠ Note: Avoid using for...in on arrays—it’s meant for objects.

2. for...of Loop

for...of is used to loop over the values of an iterable (like arrays, strings, or sets).

let colors = ["red", "green", "blue"];
 
for (let color of colors) {
  console.log(color);
}
// Output:
// red
// green
// blue

3. map() Method

map() creates a new array by applying a function to each element.

let numbers = [1, 2, 3, 4];
let squared = numbers.map(num => num * num);
 
console.log(squared); // [1, 4, 9, 16]

4. filter() Method

filter() creates a new array with elements that pass a condition.

let ages = [12, 18, 25, 30, 15];
let adults = ages.filter(age => age >= 18);
 
console.log(adults); // [18, 25, 30]

5. reduce() Method

reduce() runs a function on each element to reduce the array to a single value.

let prices = [5, 10, 15];
let total = prices.reduce((sum, price) => sum + price, 0);
 
console.log(total); // 30

 

Popular Posts

Operators (Arithmetic, Comparison, Logical)

  Operators in PHP are symbols that perform operations on variables and values. They are essential for performing calculations, comparing values, and making logical decisions in your code. PHP supports several types of operators, including arithmetic, comparison, and logical operators. Arithmetic Operators Arithmetic operators are used to perform basic mathematical operations. Example: <?php $a = 10; $b = 3;   echo $a + $b; // 13 echo $a - $b; // 7 echo $a * $b; // 30 echo $a / $b; // 3.3333 echo $a % $b; // 1 (modulus) echo $a ** $b; // 1000 (exponentiation) ?> Comparison Operators Comparison operators are used to compare two values. They return true or false . Example: <?php $x = 5; $y = 10;   var_dump($x == $y);   // false var_dump($x != $y);   // true var_dump($x === $y); // false (checks value and type) var_dump($x !== $y); // true var_dump($x > $y);    // false var_dum...
Read more

Functions (Built-in & User-defined)

  Functions in PHP are blocks of code designed to perform a specific task. They help make code reusable, organized, and easier to maintain. PHP provides built-in functions for common tasks, and also allows you to create your own user-defined functions . Built-in Functions PHP has hundreds of built-in functions that perform predefined operations such as string manipulation, mathematical calculations, and array handling. Example (Built-in Functions): <?php // String length echo strlen("Hello World"); // Outputs: 11   // Find maximum value in an array echo max(10, 20, 30); // Outputs: 30   // Convert string to uppercase echo strtoupper("php is awesome"); // Outputs: PHP IS AWESOME ?> User-defined Functions You can create your own functions to execute code whenever needed. This helps reduce repetition and makes programs easier to read. Syntax: function functionName($parameter1, $parameter2) {     // Code to...
Read more