Introduction

In this blog, you are going to learn how JavaScript built-in methods work internally. You will also learn how developers make JavaScript compatible with older browsers using polyfills.

What are polyfills :

A polyfill is a piece of JavaScript code that adds support for modern features in older browsers that don’t support them natively.

If the browser doesn’t have a feature, we create it ourselves.

Example :

Let's take an example that older browser doesn't support Array.prototype.includes.

We write polyfill like this

if ( ! Array . prototype . includes ) { Array . prototype . includes = function ( value ) { for ( let i = 0 ; i < this . length ; i ++ ) { if ( this [ i ] === value ) { return true ; } } return false ; }; }

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What are Built-in methods?

Built-in methods are predefined functions provided by the JavaScript runtime environment that are used to perform specific tasks. We don’t need to write the logic from scratch.…