ejs vs handlebars vs mustache vs pug vs nunjucks vs eta
Template Engines for Node.js Comparison
1 Year
ejshandlebarsmustachepugnunjuckseta
What's Template Engines for Node.js?

Template engines are tools that allow developers to generate HTML dynamically by embedding JavaScript logic within HTML templates. They facilitate the separation of concerns by allowing developers to define the structure of the HTML while keeping the logic in the backend. Each of these template engines has its own syntax, features, and use cases, making them suitable for different types of projects and developer preferences.

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ejs20,341,6867,850143 kB11110 months agoApache-2.0
handlebars16,658,10818,1322.78 MB992 years agoMIT
mustache5,952,92416,568-1144 years agoMIT
pug1,647,799-59.7 kB-9 months agoMIT
nunjucks1,091,6178,6351.77 MB3402 years agoBSD-2-Clause
eta783,3031,459272 kB196 months agoMIT
Feature Comparison: ejs vs handlebars vs mustache vs pug vs nunjucks vs eta

Syntax

  • ejs:

    EJS uses plain HTML with embedded JavaScript code, making it easy for developers familiar with HTML to get started. The syntax is straightforward, allowing for quick template creation.

  • handlebars:

    Handlebars uses a more structured syntax with placeholders for dynamic content and helpers for logic, promoting cleaner templates and better separation of concerns.

  • mustache:

    Mustache employs a logic-less syntax, focusing on placeholders and simple variable interpolation. This simplicity can lead to easier maintenance but may limit complex logic within templates.

  • pug:

    Pug uses indentation-based syntax, which reduces the amount of code needed to write HTML. This can enhance readability but may have a steeper learning curve for those unfamiliar with indentation-based languages.

  • nunjucks:

    Nunjucks has a rich syntax that supports template inheritance, filters, and asynchronous rendering, making it powerful for complex applications while still being relatively easy to learn.

  • eta:

    Eta features a clean and minimal syntax that is easy to read and write. It supports both inline and block-level templates, making it versatile for various use cases.

Performance

  • ejs:

    EJS is generally fast due to its straightforward rendering process. However, performance can be impacted if complex logic is embedded directly within templates.

  • handlebars:

    Handlebars performs well with precompiled templates, allowing for faster rendering at runtime. However, the use of helpers can introduce some overhead if not managed properly.

  • mustache:

    Mustache is lightweight and performs well, but its logic-less nature can sometimes lead to more complex data structures being passed to templates, which may affect performance.

  • pug:

    Pug is optimized for performance with a focus on reducing the amount of HTML code generated. However, the unique syntax may introduce a learning curve that could affect initial development speed.

  • nunjucks:

    Nunjucks can handle complex templates efficiently, but its performance may vary based on the complexity of the templates and the use of features like asynchronous rendering.

  • eta:

    Eta is designed for high performance, with features that optimize rendering speed. It supports asynchronous rendering, which can improve performance in I/O-bound applications.

Extensibility

  • ejs:

    EJS is relatively simple and does not have built-in extensibility features, but you can easily extend it with JavaScript functions and modules as needed.

  • handlebars:

    Handlebars supports custom helpers and partials, making it highly extensible for larger applications that require reusable components and logic.

  • mustache:

    Mustache's logic-less approach limits extensibility, but its simplicity allows for easy integration with various backends and frameworks without much overhead.

  • pug:

    Pug allows for mixins and includes, providing extensibility options for creating reusable components and templates, which can enhance maintainability.

  • nunjucks:

    Nunjucks is highly extensible, supporting custom filters, tags, and even asynchronous functions, making it suitable for complex applications that require tailored solutions.

  • eta:

    Eta is designed to be extensible, allowing developers to create custom tags and filters to enhance functionality and integrate with other libraries easily.

Learning Curve

  • ejs:

    EJS has a gentle learning curve, especially for developers familiar with HTML and JavaScript, making it easy to adopt for quick projects.

  • handlebars:

    Handlebars has a moderate learning curve due to its structured syntax and concepts like helpers and partials, but it promotes good practices in template design.

  • mustache:

    Mustache is easy to learn due to its simplicity, but its logic-less nature may require developers to rethink how they structure their data and templates.

  • pug:

    Pug's indentation-based syntax can be challenging for new users, but once learned, it allows for rapid development and cleaner templates.

  • nunjucks:

    Nunjucks has a steeper learning curve due to its advanced features, but it rewards developers with powerful templating capabilities once mastered.

  • eta:

    Eta is straightforward to learn, with a focus on simplicity and performance, making it accessible for new developers while still powerful for advanced users.

Community and Support

  • ejs:

    EJS has a strong community and is widely used, ensuring good support and a wealth of resources available for developers.

  • handlebars:

    Handlebars has a large community and extensive documentation, making it easy to find help and resources for troubleshooting and learning.

  • mustache:

    Mustache has a broad user base and is supported across many languages, ensuring good community support, though documentation may vary by implementation.

  • pug:

    Pug has a large community and is well-documented, providing ample resources for developers to learn and troubleshoot effectively.

  • nunjucks:

    Nunjucks benefits from a solid community and comprehensive documentation, making it easier for developers to find solutions and examples.

  • eta:

    Eta is newer and has a smaller community, but it is growing, and documentation is clear, providing adequate support for developers.

How to Choose: ejs vs handlebars vs mustache vs pug vs nunjucks vs eta
  • ejs:

    Choose EJS if you need a simple and straightforward templating engine that allows you to embed JavaScript directly into your HTML. It's great for projects where you want minimal overhead and easy integration with existing HTML.

  • handlebars:

    Opt for Handlebars if you need a powerful templating engine that supports logic-less templates and allows for reusable components. It's suitable for larger applications where maintainability and code reusability are priorities.

  • mustache:

    Use Mustache if you prefer a logic-less approach to templating. It is simple and can be used in various environments, making it a good choice for projects that require portability across different platforms.

  • pug:

    Select Pug if you want a clean and concise syntax that reduces the amount of HTML code you write. It's especially useful for projects where readability and maintainability of templates are crucial.

  • nunjucks:

    Choose Nunjucks for a feature-rich templating engine that offers powerful features like template inheritance and asynchronous control. It's perfect for complex applications that require advanced templating capabilities.

  • eta:

    Select Eta for a modern, lightweight templating engine that supports asynchronous rendering and is designed for performance. It is ideal for applications that require fast rendering times and a clean syntax.

README for ejs

Embedded JavaScript templates
Known Vulnerabilities

Security

Security professionals, before reporting any security issues, please reference the SECURITY.md in this project, in particular, the following: "EJS is effectively a JavaScript runtime. Its entire job is to execute JavaScript. If you run the EJS render method without checking the inputs yourself, you are responsible for the results."

In short, DO NOT submit 'vulnerabilities' that include this snippet of code:

app.get('/', (req, res) => {
  res.render('index', req.query);
});

Installation

$ npm install ejs

Features

  • Control flow with <% %>
  • Escaped output with <%= %> (escape function configurable)
  • Unescaped raw output with <%- %>
  • Newline-trim mode ('newline slurping') with -%> ending tag
  • Whitespace-trim mode (slurp all whitespace) for control flow with <%_ _%>
  • Custom delimiters (e.g. [? ?] instead of <% %>)
  • Includes
  • Client-side support
  • Static caching of intermediate JavaScript
  • Static caching of templates
  • Complies with the Express view system

Example

<% if (user) { %>
  <h2><%= user.name %></h2>
<% } %>

Try EJS online at: https://ionicabizau.github.io/ejs-playground/.

Basic usage

let template = ejs.compile(str, options);
template(data);
// => Rendered HTML string

ejs.render(str, data, options);
// => Rendered HTML string

ejs.renderFile(filename, data, options, function(err, str){
    // str => Rendered HTML string
});

It is also possible to use ejs.render(dataAndOptions); where you pass everything in a single object. In that case, you'll end up with local variables for all the passed options. However, be aware that your code could break if we add an option with the same name as one of your data object's properties. Therefore, we do not recommend using this shortcut.

Important

You should never give end-users unfettered access to the EJS render method, If you do so you are using EJS in an inherently un-secure way.

Options

  • cache Compiled functions are cached, requires filename
  • filename The name of the file being rendered. Not required if you are using renderFile(). Used by cache to key caches, and for includes.
  • root Set template root(s) for includes with an absolute path (e.g, /file.ejs). Can be array to try to resolve include from multiple directories.
  • views An array of paths to use when resolving includes with relative paths.
  • context Function execution context
  • compileDebug When false no debug instrumentation is compiled
  • client When true, compiles a function that can be rendered in the browser without needing to load the EJS Runtime (ejs.min.js).
  • delimiter Character to use for inner delimiter, by default '%'
  • openDelimiter Character to use for opening delimiter, by default '<'
  • closeDelimiter Character to use for closing delimiter, by default '>'
  • debug Outputs generated function body
  • strict When set to true, generated function is in strict mode
  • _with Whether or not to use with() {} constructs. If false then the locals will be stored in the locals object. Set to false in strict mode.
  • destructuredLocals An array of local variables that are always destructured from the locals object, available even in strict mode.
  • localsName Name to use for the object storing local variables when not using with Defaults to locals
  • rmWhitespace Remove all safe-to-remove whitespace, including leading and trailing whitespace. It also enables a safer version of -%> line slurping for all scriptlet tags (it does not strip new lines of tags in the middle of a line).
  • escape The escaping function used with <%= construct. It is used in rendering and is .toString()ed in the generation of client functions. (By default escapes XML).
  • outputFunctionName Set to a string (e.g., 'echo' or 'print') for a function to print output inside scriptlet tags.
  • async When true, EJS will use an async function for rendering. (Depends on async/await support in the JS runtime.
  • includer Custom function to handle EJS includes, receives (originalPath, parsedPath) parameters, where originalPath is the path in include as-is and parsedPath is the previously resolved path. Should return an object { filename, template }, you may return only one of the properties, where filename is the final parsed path and template is the included content.

This project uses JSDoc. For the full public API documentation, clone the repository and run jake doc. This will run JSDoc with the proper options and output the documentation to out/. If you want the both the public & private API docs, run jake devdoc instead.

Tags

  • <% 'Scriptlet' tag, for control-flow, no output
  • <%_ 'Whitespace Slurping' Scriptlet tag, strips all whitespace before it
  • <%= Outputs the value into the template (escaped)
  • <%- Outputs the unescaped value into the template
  • <%# Comment tag, no execution, no output
  • <%% Outputs a literal '<%'
  • %%> Outputs a literal '%>'
  • %> Plain ending tag
  • -%> Trim-mode ('newline slurp') tag, trims following newline
  • _%> 'Whitespace Slurping' ending tag, removes all whitespace after it

For the full syntax documentation, please see docs/syntax.md.

Includes

Includes either have to be an absolute path, or, if not, are assumed as relative to the template with the include call. For example if you are including ./views/user/show.ejs from ./views/users.ejs you would use <%- include('user/show') %>.

You must specify the filename option for the template with the include call unless you are using renderFile().

You'll likely want to use the raw output tag (<%-) with your include to avoid double-escaping the HTML output.

<ul>
  <% users.forEach(function(user){ %>
    <%- include('user/show', {user: user}) %>
  <% }); %>
</ul>

Includes are inserted at runtime, so you can use variables for the path in the include call (for example <%- include(somePath) %>). Variables in your top-level data object are available to all your includes, but local variables need to be passed down.

NOTE: Include preprocessor directives (<% include user/show %>) are not supported in v3.0+.

Custom delimiters

Custom delimiters can be applied on a per-template basis, or globally:

let ejs = require('ejs'),
    users = ['geddy', 'neil', 'alex'];

// Just one template
ejs.render('<p>[?= users.join(" | "); ?]</p>', {users: users}, {delimiter: '?', openDelimiter: '[', closeDelimiter: ']'});
// => '<p>geddy | neil | alex</p>'

// Or globally
ejs.delimiter = '?';
ejs.openDelimiter = '[';
ejs.closeDelimiter = ']';
ejs.render('<p>[?= users.join(" | "); ?]</p>', {users: users});
// => '<p>geddy | neil | alex</p>'

Caching

EJS ships with a basic in-process cache for caching the intermediate JavaScript functions used to render templates. It's easy to plug in LRU caching using Node's lru-cache library:

let ejs = require('ejs'),
    LRU = require('lru-cache');
ejs.cache = LRU(100); // LRU cache with 100-item limit

If you want to clear the EJS cache, call ejs.clearCache. If you're using the LRU cache and need a different limit, simple reset ejs.cache to a new instance of the LRU.

Custom file loader

The default file loader is fs.readFileSync, if you want to customize it, you can set ejs.fileLoader.

let ejs = require('ejs');
let myFileLoad = function (filePath) {
  return 'myFileLoad: ' + fs.readFileSync(filePath);
};

ejs.fileLoader = myFileLoad;

With this feature, you can preprocess the template before reading it.

Layouts

EJS does not specifically support blocks, but layouts can be implemented by including headers and footers, like so:

<%- include('header') -%>
<h1>
  Title
</h1>
<p>
  My page
</p>
<%- include('footer') -%>

Client-side support

Go to the Latest Release, download ./ejs.js or ./ejs.min.js. Alternately, you can compile it yourself by cloning the repository and running jake build (or $(npm bin)/jake build if jake is not installed globally).

Include one of these files on your page, and ejs should be available globally.

Example

<div id="output"></div>
<script src="ejs.min.js"></script>
<script>
  let people = ['geddy', 'neil', 'alex'],
      html = ejs.render('<%= people.join(", "); %>', {people: people});
  // With jQuery:
  $('#output').html(html);
  // Vanilla JS:
  document.getElementById('output').innerHTML = html;
</script>

Caveats

Most of EJS will work as expected; however, there are a few things to note:

  1. Obviously, since you do not have access to the filesystem, ejs.renderFile() won't work.
  2. For the same reason, includes do not work unless you use an include callback. Here is an example:
let str = "Hello <%= include('file', {person: 'John'}); %>",
    fn = ejs.compile(str, {client: true});

fn(data, null, function(path, d){ // include callback
  // path -> 'file'
  // d -> {person: 'John'}
  // Put your code here
  // Return the contents of file as a string
}); // returns rendered string

See the examples folder for more details.

CLI

EJS ships with a full-featured CLI. Options are similar to those used in JavaScript code:

  • -o / --output-file FILE Write the rendered output to FILE rather than stdout.
  • -f / --data-file FILE Must be JSON-formatted. Use parsed input from FILE as data for rendering.
  • -i / --data-input STRING Must be JSON-formatted and URI-encoded. Use parsed input from STRING as data for rendering.
  • -m / --delimiter CHARACTER Use CHARACTER with angle brackets for open/close (defaults to %).
  • -p / --open-delimiter CHARACTER Use CHARACTER instead of left angle bracket to open.
  • -c / --close-delimiter CHARACTER Use CHARACTER instead of right angle bracket to close.
  • -s / --strict When set to true, generated function is in strict mode
  • -n / --no-with Use 'locals' object for vars rather than using with (implies --strict).
  • -l / --locals-name Name to use for the object storing local variables when not using with.
  • -w / --rm-whitespace Remove all safe-to-remove whitespace, including leading and trailing whitespace.
  • -d / --debug Outputs generated function body
  • -h / --help Display this help message.
  • -V/v / --version Display the EJS version.

Here are some examples of usage:

$ ejs -p [ -c ] ./template_file.ejs -o ./output.html
$ ejs ./test/fixtures/user.ejs name=Lerxst
$ ejs -n -l _ ./some_template.ejs -f ./data_file.json

Data input

There is a variety of ways to pass the CLI data for rendering.

Stdin:

$ ./test/fixtures/user_data.json | ejs ./test/fixtures/user.ejs
$ ejs ./test/fixtures/user.ejs < test/fixtures/user_data.json

A data file:

$ ejs ./test/fixtures/user.ejs -f ./user_data.json

A command-line option (must be URI-encoded):

./bin/cli.js -i %7B%22name%22%3A%20%22foo%22%7D ./test/fixtures/user.ejs

Or, passing values directly at the end of the invocation:

./bin/cli.js -m $ ./test/fixtures/user.ejs name=foo

Output

The CLI by default send output to stdout, but you can use the -o or --output-file flag to specify a target file to send the output to.

IDE Integration with Syntax Highlighting

VSCode:Javascript EJS by DigitalBrainstem

Related projects

There are a number of implementations of EJS:

  • TJ's implementation, the v1 of this library: https://github.com/tj/ejs
  • EJS Embedded JavaScript Framework on Google Code: https://code.google.com/p/embeddedjavascript/
  • Sam Stephenson's Ruby implementation: https://rubygems.org/gems/ejs
  • Erubis, an ERB implementation which also runs JavaScript: http://www.kuwata-lab.com/erubis/users-guide.04.html#lang-javascript
  • DigitalBrainstem EJS Language support: https://github.com/Digitalbrainstem/ejs-grammar

License

Licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)


EJS Embedded JavaScript templates copyright 2112 mde@fleegix.org.