What is SharePoint Framework(spfx) and its key features?

Ans:- The SharePoint Framework (SPFx) is a page and web part model that provides full support for client-side SharePoint development, easy integration with SharePoint data, and support for open source tooling. With the SharePoint Framework, you can use modern web technologies and tools in your preferred development environment to build productive experiences and apps that are responsive and mobile-ready from day one. The SharePoint Framework works for SharePoint Online and also for on-premises (SharePoint 2016 Feature Pack 2 and SharePoint 2019).

Key features of the SharePoint Framework include the following:

• It runs in the context of the current user and connection in the browser. There are no iFrames for the customization (JavaScript is embedded directly to the page).
• The controls are rendered in the normal page DOM.
• The controls are responsive and accessible by nature.
• It enables the developer to access the lifecycle in addition to render, load, serialize and deserialize, configuration changes, and more.
• It is framework-agnostic. You can use any JavaScript framework that you like: React, Handlebars, Knockout, Angular, and more.
• The toolchain is based on common open source client development tools such as npm, TypeScript, Yeoman, webpack, and gulp.
• Performance is reliable.
• End users can use SPFx client-side solutions that are approved by the tenant administrators (or their delegates) on all sites, including self-service team, group, or personal sites.
• SPFx web parts can be added to both classic and modern pages.