JavaScript: 5 types of functions with 5 reasons to use each function
Tags: webdev, javascript, beginners, tutorial
Published: 2022-12-06 20:28:11

In JavaScript, there are several different types of functions that can be defined and used. Here are some of the most common types of functions in JavaScript:

## **What are Named Functions**

- Named functions: These are functions that are declared using the function keyword and are given a name. Named functions can be called by their name, and they can be assigned to a variable or passed as an argument to another function.

### Reasons to use Named Functions:

There are several reasons why you might want to use a named function in JavaScript:

1. A named function can make your code easier to read and understand, especially if the function is long or performs a complex task.

2. Using named functions can help you avoid creating global variables, which can cause conflicts with other code or libraries that you are using.

3. A named function can be easily reused in your code, which can help you avoid repeating the same code multiple times.

4. Named functions can be passed as arguments to other functions, which can be useful for implementing functional programming techniques.

5. Named functions can be used as the value of an object property, which can be useful for creating objects that have methods.

Overall, using named functions can help you write more modular and organized code that is easier to maintain and debug.

## **What are Anonymous Functions**

- Anonymous functions: These are functions that are declared without a name. Anonymous functions are typically assigned to a variable or passed as an argument to another function.

### Reasons to use Anonymous Functions:

There are several reasons why you might want to use an anonymous function in JavaScript:

1. Anonymous functions can be useful when you need to define a function that you only plan to use once, such as an event handler or a callback.

2. Anonymous functions can make your code more concise, especially if you would otherwise need to create a named function just to use it in a single location.

3. Anonymous functions can help you avoid creating unnecessary global variables, which can reduce the risk of conflicts with other code or libraries that you are using.

4. Anonymous functions are often used in functional programming techniques, such as map, filter, and reduce, which can help you write more concise and elegant code.

5. Anonymous functions can be useful when you want to define a function inside another function, which can be useful for creating nested or closure functions.

Anonymous functions are relatively new to JavaScript, if you have time be sure to try them out and let me know what you like or dislike about them!

## **What are Arrow Functions**

- Arrow functions: These are a more concise syntax for defining anonymous functions in JavaScript. Arrow functions were introduced in ECMAScript 6 (ES6) and are often used to define short, simple functions that do not need a name.

### Reasons to use Arrow Functions: 

Like all functions in JavaScript, there are several reasons why you might want to use arrow functions:

1. Arrow functions can make your code more concise, especially when defining small, one-line functions or functions that are used as arguments to other functions.

2. Arrow functions automatically bind the value of the this keyword, which can make it easier to use this inside your functions without having to worry about its value.

3. Arrow functions can be useful when you want to define a function inside another function, which can be useful for creating nested or closure functions.

4. Arrow functions are often used in functional programming techniques, such as map, filter, and reduce, which can help you write more concise and elegant code.

5. Arrow functions can be useful when you want to define a function that is not a method of an object, which can be useful for avoiding creating unnecessary this bindings.

Arrow functions are my favorite and go to. I feel they are most readable out of all functions and have many other uses!

## **What are IIFE's**

- IIFE (Immediately Invoked Function Expression) functions: These are anonymous functions that are declared and immediately executed. IIFE functions are often used to create a new scope for variables, to prevent variables from leaking into the global scope.

### Reasons to use IIFE's:

Some reasons why you might want to use an immediately invoked function expression (IIFE) in JavaScript:

1. An IIFE can be used to create a local scope for your variables and functions, which can help you avoid creating global variables and reduce the risk of conflicts with other code or libraries that you are using.

2. An IIFE can be used to create a self-contained module of code that has its own private variables and functions, which can be useful for creating reusable components or libraries.

3. An IIFE can be used to execute code immediately, without having to wait for an event, such as a page load or user interaction, to occur.

4. An IIFE can be used to define and execute a function that is only needed once, such as an event handler or a callback, without having to create a named function or create a global variable.

5. An IIFE can be used to pass arguments to a function, which can be useful for creating functions that are configurable or that can be used with different sets of data.

IIFEs in my opinion are extremely useful for organizing your code. 

## **What are Generator Functions**

- Generator functions: These are functions that use the yield keyword to return multiple values over time. Generator functions allow you to pause and resume the execution of a function, and they are often used to implement asynchronous or iterative behavior in JavaScript.

### Reasons to use Generator functions

There are several reasons why you might want to use generator functions in JavaScript:

1. Generator functions can be used to create iterable objects, which can be useful for working with large or complex data sets that cannot be easily processed or stored in memory.

2. Generator functions can be used to create lazy-evaluated or infinite sequences, which can be useful for working with data streams or large datasets that may not be known in advance.

3. Generator functions can be used to pause and resume the execution of a function, which can be useful for implementing asynchronous or concurrent programming patterns.

4. Generator functions can be used to delegate the execution of a function to another generator or iterable object, which can be useful for implementing complex control flow or data processing logic.

5. Generator functions can be used as a compact and elegant syntax for defining iterators, which can be useful for implementing the iterator protocol or creating custom iterable objects.

Overall, generator functions can be a powerful and versatile tool for working with data and implementing complex control flow in JavaScript.


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So to wrap it up, there are many different types of functions in JavaScript, and each type has its own unique characteristics and uses. Understanding the different types of functions and when to use them is an important part of learning and mastering the JavaScript language. Over time your abilities to recognize the appropriate function for your task more easily. Stick with it. These are just a few different functions, what other functions do you like or dislike?

NathanNOSudo