272 lines
9.3 KiB
Markdown
272 lines
9.3 KiB
Markdown
# EJS
|
|
|
|
Embedded JavaScript templates
|
|
|
|
[](https://travis-ci.org/mde/ejs)
|
|
[](https://david-dm.org/mde/ejs?type=dev)
|
|
[](https://snyk.io/test/npm/ejs)
|
|
|
|
## Installation
|
|
|
|
```bash
|
|
$ 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., use `<? ?>` instead of `<% %>`)
|
|
* Includes
|
|
* Client-side support
|
|
* Static caching of intermediate JavaScript
|
|
* Static caching of templates
|
|
* Complies with the [Express](http://expressjs.com) view system
|
|
|
|
## Example
|
|
|
|
```html
|
|
<% if (user) { %>
|
|
<h2><%= user.name %></h2>
|
|
<% } %>
|
|
```
|
|
|
|
Try EJS online at: https://ionicabizau.github.io/ejs-playground/.
|
|
|
|
## Usage
|
|
|
|
```javascript
|
|
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.
|
|
|
|
## 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 project root for includes with an absolute path (/file.ejs).
|
|
- `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](https://github.com/mde/ejs/releases/latest)).
|
|
- `delimiter` Character to use with angle brackets for open/close
|
|
- `debug` Output 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.
|
|
- `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.
|
|
|
|
This project uses [JSDoc](http://usejsdoc.org/). For the full public API
|
|
documentation, clone the repository and run `npm run 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 `npm run 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](https://github.com/mde/ejs/blob/master/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.
|
|
|
|
```html
|
|
<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
|
|
still supported.
|
|
|
|
## Custom delimiters
|
|
|
|
Custom delimiters can be applied on a per-template basis, or globally:
|
|
|
|
```javascript
|
|
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(" | "); $>', {users: users});
|
|
// => 'geddy | neil | alex'
|
|
```
|
|
|
|
## Caching
|
|
|
|
EJS ships with a basic in-process cache for caching the intermediate JavaScript
|
|
functions used to render templates. It's easy to plug in LRU caching using
|
|
Node's `lru-cache` library:
|
|
|
|
```javascript
|
|
let ejs = require('ejs'),
|
|
LRU = require('lru-cache');
|
|
ejs.cache = LRU(100); // LRU cache with 100-item limit
|
|
```
|
|
|
|
If you want to clear the EJS cache, call `ejs.clearCache`. If you're using the
|
|
LRU cache and need a different limit, simple reset `ejs.cache` to a new instance
|
|
of the LRU.
|
|
|
|
## Custom file loader
|
|
|
|
The default file loader is `fs.readFileSync`, if you want to customize it, you can set ejs.fileLoader.
|
|
|
|
```javascript
|
|
let ejs = require('ejs');
|
|
let myFileLoad = function (filePath) {
|
|
return 'myFileLoad: ' + fs.readFileSync(filePath);
|
|
};
|
|
|
|
ejs.fileLoader = myFileLoad;
|
|
```
|
|
|
|
With this feature, you can preprocess the template before reading it.
|
|
|
|
## Layouts
|
|
|
|
EJS does not specifically support blocks, but layouts can be implemented by
|
|
including headers and footers, like so:
|
|
|
|
|
|
```html
|
|
<%- include('header') -%>
|
|
<h1>
|
|
Title
|
|
</h1>
|
|
<p>
|
|
My page
|
|
</p>
|
|
<%- include('footer') -%>
|
|
```
|
|
|
|
## Client-side support
|
|
|
|
Go to the [Latest Release](https://github.com/mde/ejs/releases/latest), download
|
|
`./ejs.js` or `./ejs.min.js`. Alternately, you can compile it yourself by cloning
|
|
the repository and running `jake build` (or `$(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
|
|
|
|
```html
|
|
<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, `include`s do not work unless you use an `include callback`. Here is an example:
|
|
```javascript
|
|
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](https://github.com/mde/ejs/tree/master/examples) for more details.
|
|
|
|
### 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
|
|
* Jupiter Consulting's EJS: http://www.embeddedjs.com/
|
|
* 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.
|