nxus-templater
Templater Module
Templates are markup (html, ejs, etc) that Nxus modules can use to render a UX. The Templater module provides a common API for defining and accessing templates. Specifically, you can use partials and templates defined by other modules, meaning you write less code for common components.
Installation
> npm install nxus-templater --save
Parsers
Templater supports EJS and HTML as default template types. If you'd like to add in additional parsers, check out the renderer documentation.
Namespacing
All templates share a single namespace, so its a good idea to add a prefix to your template names to avoid conflicts. For example mymodule-mytemplate.ejs.
Usage
import {templater} from 'nxus-templater'
Register a Template
There are three types of templates you can register.
Template File
If you would like to register a single template, you can use the template provider and specify a file:
templater.template('path/to/some/file.ejs')
Based on the filename, the template will be given the name file and rendered using the EJS renderer.
Optionally, you can specify another template to wrap the output (for partial style templates).
templater.template('path/to/some/file.ejs', 'page')
Template Directory
Alternatively, if you have a folder with all your templates, you can add them all using templateDir.
For example, given the following directory structure:
- /templates
|- my-template.ejs
Templater will expose my-template as a new template.
templater.templateDir('path/to/some/dir/')
Each template will be processed using the template function above. You can also specify a layout that the template will be wrapped in.
templater.templateDir('path/to/some/dir/', 'page')
Alt you can specify a glob pattern to only register certain files:
templater.templateDir('path/to/some/dir/myname-*.ejs', 'page')
Function
You can also pass in a handler method instead of a file path. Templater expects that this handler returns a string with the rendered content, or a Promise that resolves to a string.
The handler will be passed in the name of the template requested, as well as any render options specified.
var handler = function(args, name) {
return "<html>.....";
}
templater.templateFunction('default', handler)
Render content using a Template
let opts = {content: "some content"}
templater.render('default', opts).then((content) => {
console.log('rendered content', content)
})
Override the template layout
If you want to specify a different layout template than was originally set, you can add a template key to the opts object.
opts.template = 'new-template'
templater.render('partial-template', opts).then((content) => {
console.log('rendered complete content', content)l
})
Render a partial from within a template
In place of EJS' include function for rendering sub-templates, you can use the render function to use a templater-registered template name within a template:
<%- render('app-nav`) %>
or with specific options
<%- render('app-nav', navItems) %>
Provide additional context opts for rendering (scripts, etc)
Modules can provide additional context options to be available to templates. :
templater.on('renderContext', () => {return {username: 'Steve'}})
The event handler is passed the original template name and args, so if req or other is provided it is available to you, or if you want to only provide context for some templates, but you do not need to return the whole modified args:
templater.on('renderContext', (args, name) => {return {username: args.req ? args.req.user : '' }})
Templater will also fire a template specific event
templater.on('renderContext.my-template', () => {return {username: 'Steve'}})
Values that are arrays are concated rather than overwritten, so that for instance scripts can collect script URLs from many modules:
templater.on('renderContext', () => {return {scripts: ['/url/script.js']}})
templater.on('renderContext', () => {return {scripts: ['/url/other.js']}})
Will result in scripts containing an array with both these values. The list will be filtered to only have unique values, so you can specify scripts in dependency order and not worry if other modules are asking for the same common js files repeatedly. The default set of templates provided by this module include rendering of this scripts variable already.
Templater API
Templater
Extends NxusModule
Templater provides template registering and rendering, built on top of the renderer
Parameters
app
template
Registers the specified template. By default, the template name will match the file name, and the renderer
used will be determined by the file extension. For example: ./templates/my-template.ejs will be registered as
my-template using the EJS rendering engine.
Parameters
-
filenameString the path of the template file to register. -
layoutString Optionally, the name of another template to use as a layout -
nameString Optional. Specify a different name to use to register the template file. (optional, defaultnull)
templateDir
Registers all templates in the specified directory.
Parameters
-
dirnameString Either a path or a glob of files to register -
layoutString Optionally, the name of another template to use as a layout -
typeString Optionally, the specific type of file to register. Defaults to all. (optional, default"*")
templateFunction
Register a handler function as a template. The registered function should return either a string or a Promise that resolves to string containing the template.
Parameters
-
nameString The name of the template. -
layoutString Optionally, the name of another template to use as a layout -
handlerFunction The handler function to use.
getTemplate
Returns the specified template if it exists
Parameters
-
nameString The name of the template.
Returns Object A template object, with type and handler attributes.
getTemplates
Returns all registered templates
Returns Object An array of template object, with type and handler attributes.
render
Render a registered template with arguments
Parameters
-
nameString The name of the template. -
argsObject Variables to make available to the template (optional, default{})
Returns Promise The rendered content as a string
Renderer Module
The rendering framework for Nxus applications.
Usage
import {renderer} from 'nxus-templater/lib/modules/renderer'
Defining a renderer
renderer.renderer(type, handler);
Where type is usually the filename extension and handler returns the rendered text when called with contents to render and an optional opts object.
Rendering a string
renderer.render(type, text).then((renderedText) => {console.log(renderedText)});
You can pass an optional arugment opts for options to pass to the renderer.
renderer.render(type, text, {title: 'My Title'}).then((renderedText) => {console.log(renderedText)});
Rendering a file
renderer.renderFile(type, filename).then((renderedText) => {});
You can pass an optional arugment opts for options to pass to the renderer.
Renderer API
Renderer
Extends NxusModule
Renderer renders different files and content using common rendering engines, like EJS and MarkDown.
Parameters
app
renderer
Provide a renderer for a particular type (file extension)
Parameters
-
typestring The type (e.g. 'html') this renderer should handle -
handlerfunction Function to receive (content, options) and return rendered content
render
Request rendered content based on type
Parameters
-
typestring The type (e.g. 'html') of the content -
contentstring The contents to render -
optsobject Options for the renderer context (optional, default{})
Returns Promise The rendered content
renderFile
Provide a renderer for a particular type (file extension)
Parameters
-
filenamestring Path to content to render -
optsobject Options for the renderer context (optional, default{})
Returns Promise The rendered content