כיצד ומדוע להשתמש בתכנות פונקציונאליות ב- JavaScript מודרני

This is how we can combine a variable number of arguments with arrow functions. Now let’s discuss Anonymous functions in JavaScript.

Anonymous Functions

An anonymous function is simply a function with no name. The purpose of using anonymous function is to perform a certain task and that task is no longer required to program. Generally, anonymous functions are declared dynamically at run time.

Example:

// Working with an Anonymous function

var a = 10; // Global Scope Variable.

// creating a function(function() {

 console.log("welcome to the world of Anonymous function");

 var b = 20; // b is a local scope variable.

 var c = a+b; // c is a local scope variable //a can be used because it is in the global scope

 console.log("Addition of two numbers value is: "+c);})();

Output

This is the concept of anonymous functions. I think I explained it in a simple and easy way.

Higher Order Functions

A higher-order function is a function that takes functions as an argument or that returns another function as a result.

The best example of higher-order functions in Javascript is that of Array.map(), Array.reduce(), Array.filter().

Example 1: Array.map()

// working with Array.map()

let myNumberArray = [4,9,16,25,36,49];

let mySquareRootArray = myNumberArray.map(Math.sqrt);

console.log(mySquareRootArray);

Output

Example 2: Array.reduce()

// working with Array.reduce()

let someRandomNumbers = [24,1,23,78,93,47,86];

function getSum(total, num){ return total + num;}

let newReducedResult = someRandomNumbers.reduce(getSum);

console.log(newReducedResult);

Output

Example 3: Array.filter()

// Working with array filter

let ages = [12,24,43,57,18,90,43,36,92,11,3,4,8,9,9,15,16,14];

function rightToVote(age){ return age >= 18;}

let votersArray = ages.filter(rightToVote);

console.log(votersArray);

Output

Recursion

This is one of the key topics in functional programming. The process in which a function calls directly or indirectly is called a recursive function. This concept of recursion is quite useful in solving algorithmic problems like the Towers of Hanoi, Pre-Order, Post-Order, In-Order, and some graph traversal problems.

Example

Let’s discuss a famous example: finding the factorial of a number using recursion. This can be done by calling the function directly from the program repeatedly. The logic for the program is

// Finding the factorial of a number using Recursion

function factorial(num){ if(num == 0) return 1; else return num * factorial(num - 1);

}

// calling the function

console.log(factorial(3));

console.log(factorial(7));

console.log(factorial(0));

Output

Characteristics Of Functional Programming

The objective of any FP language is to mimic the use of mathematical concepts. However, the basic process of computation is different in functional programming. The major characteristics of functional programming are:

Data is immutable: The data which is present inside the functions are immutable. In Functional programming, we can easily create a new Data structure but we can’t modify the existing one.

Maintainability: Functional programming produces great maintainability for developers and programmers. We don’t need to worry about changes that are accidentally done outside the given function.

Modularity: This is one of the most important characteristics of functional programming. This helps us to break down a large project into simpler modules. These modules can be tested separately which helps you to reduce the time spent on unit testing and debugging.

Advantages Of Functional Programming

1. It helps us to solve problems effectively in a simpler way.
2. It improves modularity.
3. It allows us to implement lambda calculus in our program to solve complex problems.
4. Some programming languages support nested functions which improve maintainability of the code.
5. It reduces complex problems into simple pieces.
6. It improves the productivity of the developer.
7. It helps us to debug the code quickly.

Disadvantages Of Functional Programming

1. For beginners, it is difficult to understand. So it is not a beginner friendly paradigm approach for new programmers.
2. Maintainance is difficult during the coding phase when the project size is large.
3. Reusability in Functional programming is a tricky task for developers.

Conclusion

For some, it might be a completely new programming paradigm. I hope you will give it a chance in your programming journey. I think you’ll find your programs easier to read and debug.

This Functional programming concept might be tricky and tough for you. Even if you are a beginner, it will eventually become easier. Then you can enjoy the features of functional programming.

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