eta (η)

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You're viewing the source for Eta v4

Summary

Eta is a lightweight and blazing fast embedded JS templating engine that works inside Node, Deno, and the browser. It's written in TypeScript and emphasizes great performance, configurability, and small bundle size.

🎯 Built with ts-base — A TypeScript library starter template featuring Biome, Vitest, tsdown, and automated releases. Check out ts-base for a modern TypeScript project setup!

🌟 Features

• 📦 0 dependencies
• 💡 Only ~3.5 KB minzipped
• ⚡️ Written in TypeScript
• ✨ Deno support (+ Node and browser)
• 🚀 Super Fast
• 🔧 Configurable
  • Plugins, custom delimiters, caching
• 🔨 Powerful
  • Precompilation, partials, async
  • Layout support!
• 🔥 Reliable
  • Better quotes/comments support
    • ex. <%= someval + "string %>" %> compiles correctly, while it fails with doT or EJS
  • Great error reporting
• ⚡️ Exports ES Modules
• 📝 Easy template syntax

Get Started

For more thorough documentation, visit https://eta.js.org

Install Eta

npm install eta

In the root of your project, create templates/simple.eta

Hi <%= it.name %>!

Then, in your JS file:

import { Eta } from "eta";
// or use https://jsr.io/@bgub/eta

const eta = new Eta({ views: path.join(__dirname, "templates") });

// Render a template

const res = eta.render("./simple", { name: "Ben" });
console.log(res); // Hi Ben!

FAQs

Where did Eta's name come from?

"Eta" means tiny in Esperanto. Plus, it can be used as an acronym for all sorts of cool phrases: "ECMAScript Template Awesomeness", "Embedded Templating Alternative", etc....

Additionally, Eta is a letter of the Greek alphabet (it stands for all sorts of cool things in various mathematical fields, including efficiency) and is three letters long (perfect for a file extension).

Integrations

Visual Studio Code

@shadowtime2000 created eta-vscode.

ESLint

eslint-plugin-eta was created to provide an ESLint processor so you can lint your Eta templates.

Webpack

Currently there is no official Webpack integration but @clshortfuse shared the loader he uses:

{
  loader: 'html-loader',
  options: {
    preprocessor(content, loaderContext) {
      return eta.render(content, {}, { filename: loaderContext.resourcePath });
    },
  },
}

Node-RED

To operate with Eta templates in Node-RED: @ralphwetzel/node-red-contrib-eta

Koa

To render Eta templates in Koa web framework: @cedx/koa-eta

Vite

To use Eta templates in your Vite project: @rinoshiyo/vite-plugin-eta

Projects using eta

• Docusaurus v2: open-source documentation framework that uses Eta to generate a SSR build
• swagger-typescript-api: Open source typescript api codegenerator from Swagger. Uses Eta as codegenerator by templates
• html-bundler-webpack-plugin: Webpack plugin make easily to bundle HTML pages from templates, source styles and scripts
• SmartDeno: SmartDeno is an easy to setup web template using Deno & Oak
• stc: OpenAPI (Swagger) and Apifox documentation converted to api. Use eta templates to generate code.
• Add yours!

Contributors

Made with ❤️ by bgub and many wonderful contributors. Contributions of any kind are welcome!

Credits

• Async support, file handling, and error formatting were based on code from EJS, which is licensed under the Apache-2.0 license. Code was modified and refactored to some extent.
• Syntax and some parts of compilation are heavily based off EJS, Nunjucks, and doT.