EJS (template language)

EJS (template language)
Name	EJS
Title	EJS (template language)
Programming language	JavaScript
Operating system	Cross-platform
License	MIT

EJS (template language) EJS (Embedded JavaScript) is a templating language for generating HTML and other text formats by embedding JavaScript code into templates. It is commonly used in server-side and client-side applications to render dynamic content within frameworks and platforms. EJS integrates with a variety of web servers, build tools, and hosting environments to produce view layers for applications and services.

Overview

EJS templates combine static markup with embedded JavaScript expressions and control flow statements to produce text output, enabling separation of presentation and application logic in applications built with Node.js, Deno (software), Express.js, Koa (web framework), and Fastify. Widely adopted in projects that also use React (JavaScript library) for components or AngularJS for legacy frontends, EJS is chosen for its minimal syntax and direct use of standard JavaScript, fitting into ecosystems around npm, Yarn (software), Webpack, and Parcel (software). It is often compared to alternative templating systems used in platforms such as Ruby on Rails, Django templates, and ASP.NET Razor while remaining language-native to JavaScript runtimes like V8 (JavaScript engine) and SpiderMonkey.

Syntax and Features

EJS uses delimiter tags to interpolate values and run JavaScript: evaluation tags allow execution of statements, output tags insert escaped content, and unescaped tags insert raw content. The syntax is compact and relies on core JavaScript features such as functions, arrays, and objects defined in ECMAScript, with template contexts typically provided by application frameworks like Express.js, Hapi (software), and Sails.js. EJS supports includes and partials to compose templates, similar in purpose to constructs found in Handlebars.js, Mustache (template system), Pug (template engine), and Twig (template engine). Developers leverage EJS alongside linters and formatters familiar to Airbnb JavaScript Style Guide, Prettier, and ESLint workflows.

Usage and Integration

EJS integrates as a view engine in web servers and middleware stacks such as Express.js, Koa (web framework), Fastify, and Hapi (software), allowing route handlers and controllers in applications built with NestJS or Sapper (software) to render dynamic pages. It is used in full-stack projects alongside front-end libraries like Vue.js, Angular (web framework), and React (JavaScript library) when server-side rendering or email templating is required, and works with build systems including Webpack, Rollup (software), and Gulp (software). Hosting and deployment commonly occur on platforms such as Heroku, Vercel, Netlify, and AWS Lambda, and EJS templates are often stored in repositories managed with GitHub, GitLab, or Bitbucket.

Performance and Security Considerations

Performance of EJS depends on template compilation, caching strategies, and the underlying JavaScript engine like V8 (JavaScript engine) in Chrome, Node.js, or Electron (software). Caching compiled templates at the application layer, using CDN distributions on platforms such as Cloudflare, and optimizing template composition mitigate latency in high-traffic services including microservices orchestrated with Kubernetes or Docker (software). Security considerations focus on proper escaping to prevent cross-site scripting vulnerabilities addressed by standards and best practices from organizations like OWASP; developers must avoid injecting untrusted data and follow secure coding guidance relevant to environments such as AWS, Google Cloud Platform, and Microsoft Azure.

Comparisons and Alternatives

EJS is contrasted with templating and component systems including Handlebars.js, Mustache (template system), Pug (template engine), Nunjucks, and server-side rendering approaches used by Next.js and Nuxt.js. Compared to component-driven frameworks like React (JavaScript library) and Vue.js, EJS is lighter-weight and more text-centric, similar to templating in PHP engines or view layers in Ruby on Rails and Django. Choice among these tools often depends on integration needs with platforms such as Express.js, content management systems like Strapi, and static site generators such as Gatsby (web framework) or Hugo (software).

History and Development

EJS originated as a minimal, embeddable templating approach within the JavaScript ecosystem and evolved alongside server-side JavaScript adoption driven by Node.js and web frameworks like Express.js. Its development paralleled the growth of package ecosystems managed via npm and influenced by tooling from projects such as Browserify and Webpack. Community contributions and forks have appeared on platforms such as GitHub and discussions in forums like Stack Overflow, with maintainers coordinating releases and issue triage in collaboration with broader JavaScript community events like JSConf and conferences where runtime and framework design are debated.

Category:JavaScript libraries