What are Poyfills in JavaScript ?

Polyfills in JavaScript are code snippets or scripts designed to provide modern functionality to older browsers that lack support for certain features or APIs. They act as a backwards-compatible bridge, enabling developers to use the latest ECMAScript features and web APIs across a broader range of browsers. When a browser doesn’t support a specific feature, a polyfill is employed to emulate that functionality. For example, if a browser lacks support for the `Promise` object or newer array methods like `forEach`, a polyfill can be included in the codebase to ensure consistent behaviour across different browsers. Polyfills are typically written in JavaScript and can be conditionally loaded based on feature detection. They extend the native capabilities of the JavaScript runtime environment, making it possible for developers to write more modern and efficient code without worrying about compatibility issues. While polyfills enhance cross-browser compatibility, developers should be mindful of their file size and only include polyfills for features that are genuinely needed, as unnecessary polyfills can lead to increased page load times.