Part 1 | Part 2 | Part 3 | Part 4 | Part 5 |

Of all the discussions in the Drupal community, few have generated such a proliferation of blog posts and conference sessions as decoupled Drupal, which is also the subject of a 2019 book and an annual New York conference—and has its share of risks and rewards. But one of the most pressing concerns for Drupal is how we can ensure a future for our open-source content management system (CMS) that doesn't relegate it to the status of a replaceable content repository. In short, we have to reinvent Drupal to provide not only the optimal back-end experience for developers, but also a front end that ensures Drupal's continued longevity for years to come.

A few months ago, Fabian Franz (Senior Technical Architect and Performance Lead at Tag1 Consulting) offered up an inspirational session that presents a potential vision for Drupal's front-end future that includes Web Components and reactivity in the mix. In Fabian's perspective, by adopting some of the key ideas that have made popular JavaScript frameworks famous among front-end developers, we can ensure Drupal's survival for years to come.

In this multi-part blog series that covers Fabian's session in detail from start to finish, we summarize some of the key ideas that could promise an exciting vision not only for the front-end developer experience of Drupal but also for the user experience all Drupal developers have to offer their customers. In this fifth installment in the series, we continue our analysis of some of the previous solutions we examined and consider some of the newfangled approaches made possible by this evolution in Drupal.

The "unicorn dream"

Before we get started, I strongly recommend referring back to the first, second, third, and fourth installments of this blog series if you have not already. They cover essential background information and insight into all of the key components that constitute the vision that Fabian describes. Key concepts to understand include Drupal's render pipeline, virtual DOMs in React and Vue, the growing Twig ecosystem, universal data stores, and how reactivity can be enabled in Drupal.

One of the final questions Fabian asks in his presentation is about the promise unleashed by the completion of work to enable shared rendering in Drupal, as well as reactivity and offline-enabled functionality. During his talk, Fabian recalls a discussion he had at DrupalCon Los Angeles with community members about what he calls the unicorn dream: an as-yet unfulfilled vision to enable the implementation of a Drupal site front end with nothing more than a single index.html file.


Fabian argues that the component-driven approach that we have outlined in this blog series makes this unicorn dream possible thanks to slots in Web Components. Because React, Vue, and Twig all have slots as part of their approaches to componentization, this possibility becomes more possible than ever before. Front-end developers can insert repeatable blocks with little overhead while still benefiting from configuration set by editors who don't touch a single line of code but that affects rendered output. Developers can extend said block rather than overriding the block.

Consider, for instance, the following example that illustrates leveraging an attribute to override the title of a block:

    <sidebar type="left">
      <block slot="header" id="views:recent_content">
        <h2 slot="title">I override the title</h2>

When Fabian attempted to do this with pure Twig, he acknowledges that the complexity quickly became prohibitive to proceed, and the prototype never reached core-readiness. However, thanks to this approach using Web Components slots, one could create plugins for modern editors that would simply use and configure custom elements. Among editors that would support this hypothetical scenario are heavyweights like CKEditor 5, ProseMirror (which Tag1 recently selected as part of a recent evaluation of rich-text editors), and Quip.

Developer experience improvements

This means that we as developers no longer have the need to convert the display of tokens through a variety of complex approaches. Instead, we can simply render HTML and directly output the configured component; Drupal will handle the rest:

    <drupal-image id="123" />

Moreover, leveraging BigPipe placeholders with default content finally becomes simple thanks to this approach, argues Fabian. We can simply place default content within the component, and once the content arrives, it becomes available for use:

    <block id="views:recent_content" drupal-placeholder="bigpipe">
      I am some default content!

In this way, we can take advantage of our existing work implementing BigPipe in Drupal 8 rather than resorting to other JavaScript to resolve this problem for us.

Performance improvements

Finally, some of the most important advancements we can make come in the area of performance. For front-end developers who need to serve the ever-heightening demands of customers needing the most interactive and reactive user experience possible, performance is perennially a paramount consideration. When using a universal data store, performance can be improved drastically, particularly when the store is utilized for as many data requirements as possible.

We can simply update the real-time key-value store, even if this happens to solely be located on Drupal. As Fabian argues, a data-driven mindset makes the problem of shared rendering and componentization in Drupal's front end much simpler to confront. Developers, contends Fabian, can export both the data and template to a service such as Amazon S3 and proceed to load the component on an entirely different microsite, thus yielding benefits not only for a single site but for a collection of sites all relying on the same unified component, such as &lt;my-company-nav />.

Such an approach would mean that this company-wide navigation component would always be active on all sites requiring that component, simplifying the codebase across a variety of disparate technologies.

Editorial experience improvements

Nonetheless, perhaps some of the most intriguing benefits come from improvements to the editorial experience and advancements in what becomes possible despite the separation of concerns. One of the chief complaints about decoupled Drupal architectures, and indeed one of its most formidable disadvantages, is the loss of crucial in-context functionality that editors frequently rely on on a daily basis such as contextual links and in-place editing.

With Fabian's approach, the dream that formerly seemed utterly impossible of achieving contextual administrative interfaces within a decoupled Drupal front end become not only possible but realistic. We can keep key components of Drupal's contextual user interface such as contextual links as part of the data tree rather than admitting to our customers that such functionality would need to vanish in a scenario enabling greater reactivity and interactivity for users.

After all, one of the key critiques of decoupled Drupal and JavaScript approaches paired with Drupal, as I cover in my book Decoupled Drupal in Practice, is the lack of support for contextual interfaces and live preview, though I've presented on how Gatsby can mitigate some of these issues. Not only does this solution allow for contextual interfaces like contextual links to remain intact; it also means that solutions like progressive decoupling also become much more feasible.

Moreover, one of the key benefits of Fabian's approach is Drupal's capacity to remain agnostic to front-end technologies, which guarantees that Drupal is never coupled to a framework that could become obsolete in only a few years, without having to reinvent the wheel or create a Drupal-native JavaScript framework. And one of the key defenses of Fabian's vision is this rousing notion: We can potentially enable single-page applications with Drupal without having to write a single line of JavaScript.

Outstanding questions

Despite the rousing finish to Fabian's session, pertinent questions and concerns remain about the viability of his approach that were borne out during the Q&A session following the session. One member of the audience cited the large number of examples written in Vue and asked whether other front-end technologies could truly be used successfully to implement the pattern that Fabian prescribes. Fabian responded by stating that some work will be necessary to implement this in the framework's own virtual DOM, but in general the approach is possible, as long as a customizable render() function is available.

Another member of the audience asked how Drupal core needs to evolve in order to enable the sort of future Fabian describes. Fabian answered by recommending that more areas in Drupal responsible for rendering should be converted to lazy builders. This is because once no dependencies in the render tree are present, conversion to a component tree would be much simpler. Fabian also cited the need for a hook that would traverse the DOM to discover custom components after each rendering of the Twig template. Thus, the main difference would be writing HTML in lieu of a declaration in Twig such as {% include menu-item %}.


In this fifth and final installment of our multi-part blog series about a visionary future for Drupal's front end, we examined Fabian's rousing DrupalCon Amsterdam session to discuss some of the benefits that reactivity and offline-first approaches could have in Drupal, as well as a framework-agnostic front-end vision for components that potentially extends Drupal's longevity for many years to come. For more information about these concepts, please watch Fabian's talk and follow our in-house Tag1 Team Talks for discussion about this fascinating subject.

Special thanks to Fabian Franz and Michael Meyers for their feedback during the writing process.

Part 1 | Part 2 | Part 3 | Part 4 | Part 5 |

For more on Web Components and how they're being used, see Web Components.

Photo by Stephen Leonardi on Unsplash