A polyfill mimics a future API providing fallback functionality to older browsers.
Polyfills are commonly used to provide support for new features such as Promises, Arrow Functions, and Fetch API, which were introduced in ECMAScript 6 (ES6). They are also used to support newer APIs such as Web Audio API, Web Speech API, and many others.
Array.includes: Check whether an element exists in an array or not.
Object.assign: Copy the values of all enumerable properties from one or more source objects to a target object.
String.startsWith: Check whether a string starts with a specified substring.
Array.from: Create a new array from an iterable object.
Object.entries: return an array of a given object’s own enumerable property [key, value] pairs.
Array.find: Find the first element in an array that satisfies a given condition.
This page provides a list of commonly used polyfills for various HTML5 features, including HTML5 forms, HTML5 media elements, and HTML5 APIs.
Polyfills work by first checking if the feature is already supported by the browser. If the feature is supported, then the polyfill is not needed, and the code can run as intended. However, if the feature is not supported, the polyfill is loaded, and the code is modified to replicate the behavior of the new feature.
Another advantage of using polyfills is that they can improve the performance of web applications. Polyfills are typically lightweight, and they only load the code that is needed to replicate a specific feature. This means that developers can avoid loading larger, more complex libraries that are designed to provide broader support.
One of the main disadvantages of using polyfills is that they can slow down the performance of web applications if they are not used correctly. Polyfills can add additional code to a web page, which can increase the file size and slow down page load times. Additionally, some polyfills may not be optimized for performance, which can result in slower execution times and reduced overall performance.