Jake JavaScript build tool

<%= EJS %>

Embedded JavaScript templating.

What is EJS?

What is the "E" for? "Embedded?" Could be. How about "Effective," "Elegant," or just "Easy"? EJS is a simple templating language that lets you generate HTML markup with plain JavaScript. No religiousness about how to organize things. No reinvention of iteration and control-flow. It's just plain JavaScript.

Use plain JavaScript

We love JavaScript. It's a totally friendly language. All templating languages grow to be Turing-complete. Just cut out the middle-man, and use JS!

Fast development time

Don't waste time and attention figuring out arcane new syntax because 'elegance' — or how to preprocess your data so it will actually render right.

Simple syntax

JavaScript code in simple, straightforward scriptlet tags. Just write JavaScript that emits the HTML you want, and get the job done!

Speedy execution

We all know how fast V8 and the other JavaScript runtimes have gotten. EJS caches the intermediate JS functions for fast execution.

Easy debugging

It's easy to debug EJS errors: your errors are plain JavaScript exceptions, with template line-numbers included.

Active development

EJS has a large community of active users, and the library is under active development. We're happy to answer your questions or give you help.

Features

Get Started

Install

It's easy to install EJS with NPM.

$ npm install ejs

Use

Pass EJS a template string and some data. BOOM, you've got some HTML.

let ejs = require('ejs');
let people = ['geddy', 'neil', 'alex'];
let html = ejs.render('<%= people.join(", "); %>', {people: people});

CLI

Feed it a template file and a data file, and specify an output file.

ejs ./template_file.ejs -f data_file.json -o ./output.html

Browser support

Download a browser build from the latest release, and use it in a script tag.

<script src="ejs.js"></script>
<script>
  let people = ['geddy', 'neil', 'alex'];
  let html = ejs.render('<%= people.join(", "); %>', {people: people});
</script>

Docs

Example

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

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
});

Options

  • cache Compiled functions are cached, requires filename
  • filename Used by cache to key caches, and for includes
  • root Set project root 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 Returns standalone compiled function
  • delimiter
  • openDelimiter
  • closeDelimiter '/li>
  • 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. (Implies `--strict`)
  • 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.

Tags

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

Includes

Includes are relative to the template with the include call. (This requires the 'filename' option.) For example if you have "./views/users.ejs" and "./views/user/show.ejs" you would use <%- include('user/show'); %>.

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>

CLI

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

  • cache Compiled functions are cached, requires filename
  • -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.

Some examples of use:

$ 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

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('<?= users.join(" | "); ?>', {users: users},
    {delimiter: '?'});
// => 'geddy | neil | alex'

// Or globally
ejs.delimiter = '$';
ejs.render('<$= users.join(" | "); $>', {users: users});
// => 'geddy | neil | alex'

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 myFileLoader = function (filePath) {
  return 'myFileLoader: ' + 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

Using EJS with Express

This GitHub Wiki page explains various ways of passing EJS options to Express.

Support

Stack Overflow

Ask questions about specific problems you have faced, including details about what exactly you are trying to do. Make sure you tag your question with ejs. You can also read through existing ejs questions.

GitHub issues

The issue tracker is the preferred channel for bug reports, features requests and submitting pull requests.

License

EJS is licensed under the Apache License, version 2.0. Information can found here: http://www.apache.org/licenses/.