View

Introduced in 3.0.0

Stability: 2 - Stable

const View = require('kado/lib/View')

This library provides the registration of both view engines for rendering with various languages as well, as a view registry of actual fixtures to render from.

Class: View

View extends Connect see Connect for more engine management and more.

static View.getInstance()

• Return {View} new instance of the View system

View.constructor()

• Return {View} new instance of the View system

Class: ViewEngine

ViewEngine extends ConnectEngine see ConnectEngine for more engine management and more.

ViewEngine.render()

Must be extended and used to render to the underlying system.

Class: ViewMustache

An extension of ViewEngine made to work with the Mustache template system and implements a partial loader for working with a folder of templates.

Usage

  // add a view engine
  const fs = require('kado/lib/FileSystem')
  const ViewMustache = require('kado/lib/View').ViewMustache
  const viewFolder = fs.path.join(__dirname, 'main/views')
  app.view.addEngine('mustache', new ViewMustache(viewFolder))
  app.view.activateEngine('mustache')

Middleware

The View Mustache engine also provides middleware that can be used to add global post-processing actions to any render call. Below is an example of how to set this up.

The view middleware process uses latent object modification to allow control over the view. This means that rather than returning any value, each portion of the object passed to the middleware can be updated to a new value.

Here is an example of the view passed to the middleare.

const view = {
  body: body, // the current output body
  options: options, // options passed to the original render call
  params: params, // parameters passed to the render
  partials: partials, // partials that were looked up during render
  req: req, // the request
  res: res, // the response
  tags: tags, // mustache tag overrides
  template: template // template resolved during render
}

The return value does control the flow. When true is returned the middleware processing stops and the view engine does not output anything. Any other value will process all middleware and then output the view.

DISCLAIMER

This middleware should only be used for global uses. Using them will confuse the flow of the controller code and add magic that has to be discovered by the next coder. As such, the use is slightly discouraged while the functionality can be helpful. If possible, please fix the problem or correct the output within the controller.

Example

While in the process of setting up the application. Typically, within lib/App.js the following portion will need adjusted.

// add a view engine
const viewFolder = fs.path.join(__dirname, '..', 'view')
app.view.addEngine('mustache', new View.ViewMustache(viewFolder))
app.view.activateEngine('mustache')

Now with middleware

// setup view engine
const viewFolder = fs.path.join(__dirname, '..', 'view')
const viewEngine = new View.ViewMustache(viewFolder)
// add middleware
viewEngine.use((view) => {
  if (view.body.match('stuff')) {
    res.statusCode = 404
    res.end('Not found')
    return true // halt middleware processing since the response was sent
  }
})
viewEngine.use((view) => {
  if (view.params.captchaEnabled) view.params.captchaKey = 'something'
})
viewEngine.use((view) => {
  if (!req.isJSON) return // continue through middleware
  res.json(view.params)
  return true // halt middleware processing since the response was sent
})
// add a view engine
app.view.addEngine('mustache', viewEngine)
app.view.activateEngine('mustache')