Working with placeholders in a JSS Next.js app

The most common way to add a placeholder to a component is to use the Placeholder component.

import { Placeholder } from '@sitecore-jss/sitecore-jss-nextjs';

const App = ({ rendering }) => (
  <div>
    <h1>My App</h1>
    <Placeholder name="jss-main" rendering={rendering} />
  </div>
);

For the Placeholder component:

The higher-order component (HOC) pattern lets you get an array of the components in a placeholder injected as a property to the component that exposes the placeholder.

import { withPlaceholder } from '@sitecore-jss/sitecore-jss-nextjs';

const Tabs = ({ tabs }) => {
  return (
    <div>
      {tabs}
    </div>
  );
};

export default withPlaceholder('tabs')(Tabs);

When you emit the component array, the application renders the components where you emit them.

If you emit the placeholder with the HOC technique, the placeholder has no wrapping component and renders inline. The HOC approach is useful when you are using libraries based on a specific component hierarchy. If you use the basic placeholder technique, all child components render underneath it in the component tree.

For example, if you want to use the react-fullpage library with the following structure:

<SectionsContainer>
  <Section color="#69D2E7">Page 1</Section>
  <Section color="#A7DBD8">Page 2</Section>
  <Section color="#E0E4CC">Page 3</Section>
</SectionsContainer>

The library expects the following component hierarchy:

SectionsContainer
    Section

However, if you add the Section components using the basic placeholder technique:

<SectionsContainer>
  <Placeholder name="jss-sections" rendering={rendering} />
</SectionsContainer>

the resulting component hierarchy is:

SectionsContainer
    Placeholder    
        YourComponent 
            Section

With the HOC-based placeholder, you can use inline components or component transformation to achieve a flatter component hierarchy.

SectionsContainer
    YourComponent 
        Section

import { withPlaceholder } from '@sitecore-jss/sitecore-jss-nextjs';

const ContainerComponent = ({ sectionsPlaceholder }) => {
  return <SectionsContainer>{sectionsPlaceholder}</SectionsContainer>;
};

// you can also alias the property for the placeholder when using the HOC - or pass an array of placeholders
export const ContainerSitecoreComponent = withPlaceholder({ placeholder: 'sections', prop: 'sectionsPlaceholder' })(ContainerComponent);

// the <Section> is in the child Sitecore component added to the placeholder
export const ChildSitecoreComponent = (props) => (
  <Section>
    <h1>Your components here</h1>
  </Section>
);

SectionsContainer
    Section

const ContainerComponent = ({ sectionsPlaceholder }) => {
  return (
    <SectionsContainer>
      {sectionsPlaceholder.map((component, index) => {
        // this if is important, as it prevents breakage when using Sitecore Experience Editor
        if (component.props && component.props.type === 'text/sitecore') return component;

        // wraps _all_ child components in a <Section> component
        return <Section key={index}>{component}</Section>;
      })}
    </SectionsContainer>
  );
};

export const ContainerSitecoreComponent = withPlaceholder({ placeholder: 'sections', prop: 'sectionsPlaceholder' })(ContainerComponent);

JSS supports the render props pattern as an alternative to higher-order components. Using the render property of the <Placeholder> component, you can take over the rendering of placeholder contents the same way as with the higher-order component and use dynamic properties.

The following example illustrates how to get the components array and render it using render property.

import { Placeholder } from '@sitecore-jss/sitecore-jss-nextjs';

const App = ({ rendering }) => (
  <div>
    <h1>My App</h1>
    <Placeholder name="jss-main" rendering={rendering} render={(components, placeholderData, props) => <div>{components}</div>} />
  </div>
);

You can use two optional arguments to the render function of the placeholder:

You can access the data of a placeholder instead of its components, for example, for components such as tabs that you want to render in two places (the tab title and the tab contents). Because the placeholder hierarchy is a big JavaScript object, you can traverse it using props.rendering to discover child component data and fields.

const Tabs = ({ rendering, tabs }) => (
<Tab.Container>
  <div class="tabsHeading">
    {(rendering.placeholders.tabs || [])
      .filter((tab) => tab && tab.fields && tab.fields.title)
      .map((tab, index) => (
        <Tab.Heading key={index}>
          <Text field={tab.fields.title} />
        </Tab.Heading>
      ))}
  </div>

  <div class="tabContents">
    {tabs}
  </div>
</Tab.Container>
);

export default withPlaceholder('tabs')(Tabs);

Placeholders provide options for enhancing the developer/editor experience by using custom components. If you use the basic placeholder technique, you can configure which custom components the placeholder renders for errors or missing JavaScript implementations with the help of the Placeholder component properties. If you use the HOC pattern, you can use the propsTransformer option to inject the same properties using a function.