navigation

Navigation
Navigation is inspired by turbolinks.
Visit and Remote
Superglue comes with two thunks that wrap around fetch:
1.visit is used for page-to-page navigation, there can be only one visit at a time.
2.remote is used with urls that contain the props_at param for partial page updates.
When configuring your application in application.js, your page components would all receive a visit and remote function that will dispatch when called.
application_visit.js
Out of the box, the visit thunk is bare, it doesn't navigate on success or specify any behavior on error. We have to enhance it with sane defaults for the web then inject it into your application to override the thunk.
If you've used the generators, this is done for you in application_visit.js and the resulting visit is injected in application.js.
You can add customizations to visit or remote in application_visit.js.
Single page navigation using visit
Single page navigation must be explicitly enabled using a data attribute​
  <a href='/posts' data-sg-visit={true} />
or manually called using the visit thunk somewhere in your component:
  this.props.visit("/posts", {...options})
    .then(...) #add navigateTo
Options passed to visit are also passed to fetch. Additionally, there are two features that enable low effort interactivity.
placeholders
The idea of placeholders is to optimistically copy the current page state over to the next page's state before the request. This is handy if the next page looks almost identical to the current page. Use cases include:
1.Modals
2.Providing content for manual deferments
Example:
  <a
    href='/posts/new?props_at=data.body.modal'
    data-sg-visit={true}
    data-sg-placeholder="/new"
  />
or
  this.props
    .visit("/posts/new?props_at=data.body.modal", { placeholderKey: "/new"})
    .then(...) #add navigateTo
beforeSave
You can provide a callback that will modify the page before it gets saved to the Redux store. Very handy for chat applications that need to merge the current page's messages with the next one.
Example:
  const beforeSave = (prevPage, nextPage) => {
    nextPage.data.messages = [
      prevPage.data.messages,
      ... nextPage.data.messages
    ]
​
    return nextPage
  }
​
  this.props.visit("/posts", {beforeSave}).then(...) #add navigateTo
Partial page updates with remote
remote combined with the props_at parameter can update any part of the Redux store in the background. Most of the time, you would be using this thunk to update the current page the user is seeing. Like visit, you can provide a beforeSave callback to modify content before it gets saved to the store.
  const beforeSave = (prevPage, nextPage) => {
    nextPage.data.messages = [
      prevPage.data.messages,
      ... nextPage.data.messages
    ]
​
    return nextPage
  }
​
​
  this.props.remote("/posts?props_at=data.header", {beforeSave})
You may also specify a pageKey param to tell Superglue where to store the results. If you're using the thunk through a connected component, this will be set to the key of the current page for you.
Deferments
Deferments are a low effort way to load content in async fashion, both automatically and manually.
auto
  json.metrics(defer: [:auto, placeholder: {total_visitors: 0}]) do
    sleep 10 # expensive operation
    json.total_visitors 30
  end
When visiting the above, PropsTemplate will render with
{
  metrics: {
    total_visitors: 0
  }
}
Then make a remote("/dashboard?props_at=data.metrics") call and 10 seconds later, {total_visitors: 30} will be immutably grafted into the same position on the Redux store and React will rerender. For more control, you may provide a success_action or fail_action, and Superglue will dispatch these actions when the promise resolves successfully or fails.
json.metrics(defer: [:auto, placeholder: {total_visitors: 0}, success_action: "SUCCESS", fail_action: "FAIL"]) do
  sleep 10 # expensive operation
  json.total_visitors 30
end
manual
Using manual with deferment means that a remote call will not take place, it is up to you to fetch the node using remote yourself.
json.metrics(defer: [:manual, placeholder: {total_visitors: 0}]) do
  sleep 10 # expensive operation
  json.total_visitors 30
end