Client-Side Rendering As An Alternative To Html Markup In Calculated Columns

What is Client-Side Rendering and Why Use It?

Client-side rendering refers to generating markup and rendering web page content in the user’s web browser rather than on the web server. With client-side rendering, the initial page load contains minimal HTML, CSS and JavaScript code. Once loaded, JavaScript code fetches data from an API and uses it to construct HTML components to display the full page content.

The key benefits of client-side rendering include:

• Improved performance – By offloading rendering to the client, server load is reduced leading to faster response times.
• Dynamic updates – Content can be updated in real-time without needing full page reloads.
• Rich interactivity – Sophisticated UI effects and interactions can be implemented using JavaScript frameworks.

Limitations of Calculated Columns in SharePoint

SharePoint calculated columns provide basic formatting and display logic for data in list forms and views. However, they have some significant limitations:

• Limited HTML markup – Calculated columns only allow a subset of HTML tags for formatting text.
• No complex rendering – Dynamic effects, conditional formatting, animations etc. are not possible.
• Server-side only – Logic runs during page generation on the server limiting interactivity.

These constraints mean calculated columns are not suitable for complex rendering needs or rich client-side experiences.

Using Client-Side Code Instead

To overcome the limitations with calculated columns, client-side JavaScript code can be used instead:

• Script Editor web part – Insert JavaScript files or snippets that execute on page load.
• Content Editor web part – Reference external JS files hosted on CDNs.
• Call SharePoint REST API – Retrieve list data client-side for rendering.
• Client-side frameworks – Use React, Vue, Angular to build interactive UI components.

This approach provides full control over markup while leveraging client resources for performance.

Building a React Application as a Calculated Column Alternative

An example scenario is using React to build an application that replaces a calculated column:

• Fetch data from /_api/web/lists REST endpoint to get list contents.
• Iterate through items and use React framework to render UI components.
• Conditional rendering, effects, transitions etc. can be implemented.

Sample code:

  const App = () => {

  const [items, setItems] = React.useState([]);

  React.useEffect(() => {
    fetch('/_api/web/lists/getbytitle('List')/items')
    .then(res => res.json())
    .then(data => setItems(data))
  }, []);

  return (
    <div>
      {items.map(item => (
        <div> 
          <h3>{item.Title}</h3>
          <p>{item.Description}</p>
        </div>
      ))}
    </div>
  )}

ReactDOM.render(<App />, document.getElementById('root'));  

This shows how React can consume SharePoint data and use it to construct UIs with any required rendering logic.

Considerations When Using Client-Side Solutions

When leveraging client-side code instead of calculated columns, some considerations include:

• Cross-browser compatibility – Test across target browsers.
• Governance policies – Evaluate security, compliance and governance requirements.
• Development costs – Weigh initial dev time versus long-term flexibility.
• Skill requirements – May require JavaScript framework knowledge.

These should all factor into decisions around utilizing client-side techniques.

The Scalability and Customization Upsides

The benefits of implementing client-side solutions include:

• Scalability – By offloading work to the client, server loads are reduced allowing for easier scale.
• Customization – Fully customize rendering and UIs vs. constraints with calculated columns.
• Latest web capabilities – Utilize modern JS frameworks for advanced functionality.
• App-style experiences – Mimic sleek application UIs and interfaces inside SharePoint.

These upsides enable experiences not otherwise possible using OOTB calculated columns.

Conclusion

Replacing server-rendered calculated columns with client-side solutions opens up many possibilities for dynamic and interactive experiences in SharePoint.

While requiring thoughtful planning around elements like security and cross-browser compatibility, client-side rendering enables rendering scenarios involving complex logic, real-time updates, and rich effects not possible using declarative calculated columns.

By leveraging modern web technologies like React, Vue and Angular within the SharePoint context, UI capabilities can be expanded greatly over relying on server-side OOTB functionality.

The combination of SharePoint backend services and flexible front-end rendering makes client-side solutions an intriguing alternative to explore for creating engaging, app-like interfaces and experiences.