JS Template Literals Engine
a very basic, and straight to the point Template Engine using JS Template Literals
Why
Template Literals (also known as "Template strings") are a familiar and simple to use method to run embedded expressions and string interpolation, which are the primary functionality of a Template Engine.
This library wraps template literals with traditional techniques (layouts, partials, helpers, etc ...) to facilitates the usage through a structured file format (.jstl)
What
Features:
- Layouts: native support for layouts
- Partials Support: include files and pass data with ease
- Fast: Templates are cached by default
- Extensible: extensible with custom helpers
How
Usage
template.jstl
hello ${data.name}
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine(options)
engine.render('template', { name: 'ahmad' })
String Interpolation
since templates are parsed as standard JavaScript Template Literals the same functionality is expected
Variables are accessible data context
Example
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine()
const result = engine.render('template', { name: 'ahmad' })
console.log(result)
template.jstl
Hello ${data.name}
result
$ node index.js
Hello ahmad
Helper functions
Helpers are essentially functions that can be called within the template.
All helper functions are available through the fn context
Example
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine({
helpers: {
capitalize : str => string[0].toUpperCase() + string.slice(1)
}
})
const result = engine.render('template', { name: 'ahmad' })
console.log(result)
template.jstl
Hello ${fn.capitalize(data.name)}
result
$ node index.js
Hello Ahmad
Built-in Helpers
fn.render(templateName, [dataObject])
Behaves exactly like Engine.render by including other template file: templateName inline
fn.apply(templateName, [dataArray])
enumerates over dataArray and applies each item to a newly rendered instance of templateName
Example
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine()
const actors = [
{ name: 'William Hartnell', year: '1963' },
{ name: 'Patrick Troughton', year: '1966' },
{ name: 'Jon Pertwee', year: '1970' },
{ name: 'Tom Baker', year: '1974' },
{ name: 'Peter Davison', year: '1981' },
{ name: 'Colin Baker', year: '1984' },
{ name: 'Sylvester McCoy', year: '1987' },
{ name: 'Paul McGann', year: '1996' },
{ name: 'Christopher Eccleston', year: '2005' },
{ name: 'David Tennant', year: '2005' },
{ name: 'Matt Smith', year: '2010' },
{ name: 'Peter Capaldi', year: '2013' },
{ name: 'Jodie Whittaker', year: '2017' }
]
const result = engine.render('page', { actors })
console.log(result)
page.jstl
${ fn.include('header') }
<h1>List of actors who have played the Doctor</h1>
<ul>
${ fn.apply('doctor', data.actors) }
</ul>
${ fn.include('footer') }
doctor.jstl
<li>${data.name} - first appeared in ${data.year}</li>
result
$ node index.js
<body>
<h1>List of actors who have played the Doctor</h1>
<ul>
<li>William Hartnell - first appeared in 1963</li>
<li>Patrick Troughton - first appeared in 1966</li>
<li>Jon Pertwee - first appeared in 1970</li>
<li>Tom Baker - first appeared in 1974</li>
<li>Peter Davison - first appeared in 1981</li>
<li>Colin Baker - first appeared in 1984</li>
<li>Sylvester McCoy - first appeared in 1987</li>
<li>Paul McGann - first appeared in 1996</li>
<li>Christopher Eccleston - first appeared in 2005</li>
<li>David Tennant - first appeared in 2005</li>
<li>Matt Smith - first appeared in 2010</li>
<li>Peter Capaldi - first appeared in 2013</li>
<li>Jodie Whittaker - first appeared in 2017</li>
</ul>
</body>
Front Matter
Every template file can optionally include a front matter block, which is parsed and included into the data context
Example
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine()
const result = engine.render('template')
console.log(result)
template.jstl
---
name: ahmad
---
Hello ${data.name}
result
$ node index.js
Hello ahmad
Layouts
defining a layout property in the Front Matter block of a template will result in rendering that layout first and including the current template as content.
Layouts can infinitely cascade, the only limit is your system resources!
Example
index.js
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine()
const result = engine.render('template', { name: 'ahmad' })
console.log(result)
template.jstl
---
layout: layouts/welcome
---
<h2>${data.name}</h2>
layouts/welcome.jstl
---
layout: layouts/base
---
<h1>Welcome!</h1>
${data.content}
layouts/base.jstl
<html>
<body>
${data.content}
</body>
</html>
result
$ node index.js
<html>
<body>
<h1>Welcome</h1>
<h2>ahmad</h2>
</body>
</html>
API
Constructor new Engine([optionsObject])
returns a new instance of the template engine class
| name | type | required | default | description |
|---|---|---|---|---|
root | String | ✖ | process.cwd() | path to look for template files |
extension | String | ✖ | jstl | template file extension |
helpers | Object | ✖ | {} | key => function helpers map to pass to templates |
matter | Object | ✖ | {} | Options to pass to gray-matter |
example:
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine({
root: 'templates',
extension: 'html'
helpers: {
capitalize : str => string[0].toUpperCase() + string.slice(1),
...
}
})
Method: render(templateName, [dataObject])
parses the content of the file at ${templateName}.jstl and passes dataObject to it, returns the processed output string
example:
const Engine = require('@ahmadnassri/template-literals-engine')
const engine = new Engine({ root: 'templates' })
engine.render('a-template') // => ./templates/a-template.jstl
engine.render('nested/template', { foo: 'bar' }) // => ./templates/nested/template.jstl
Author: Ahmad Nassri • Twitter: @AhmadNassri