Arrow Functions vs. Regular Functions in JavaScript

JavaScript offers two ways to declare a function: the function keyword and the arrow syntax. While both create similar results, they differ in scope accessibility. It is important for modern JS developers to understand how each function declaration affects scope and visibility.

Arrow functions are an alternative way to define functions that don’t use the default function keyword. They were first adopted with the release of the ECMAScript 2015 standards and offered a clean and concise way to quickly create functions and solve long-running scope issues within JavaScript. Arrow functions have become a hit among many developers and are just as likely to be found as regular functions in modern JavaScript codebases.

Despite the similarities between the two, there are some differences that developers need to be aware of. Whenever a regular function is declared in JavaScript, that function works as a closure that creates its own scope. This can cause an issue when using certain specialized functions like setTimeout and setInterval. Prior to ES6, there were a significant number of workarounds that would hoist items to higher levels of scope for use in callbacks. These hacks worked, but they were often difficult to understand and could cause problems with certain variables getting overwritten.

Arrow functions solved both issues in a simple and elegant way. When an arrow function is used as a part of a callback, it has access to the same scope as the function from which it was called. This allowed functions to be used as callbacks without losing access to the context in which the original event was called. Arrow functions are also used to keep code clean and concise, making it more readable and simpler to compose objects.

JavaScript’s arrow functions are an incredibly powerful feature that gives developers far more control over what scope a function has access to. Knowing when a callback should have access to its parent’s scope, and when it shouldn’t, can help a developer determine which type of declaration to use. Arrow functions give programmers a clear and concise way to write callbacks without exposing parts of the scope that should be hidden. They also allow for the creation of clean and simple compositions, further enabling functional programming in JavaScript.

Source: MakeUseOf

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