Gatsby Kontent Components

The package containing React components useful when processing Kontent data to the site.

To see the progress of the Gatsby v4 supported packages - check out this pull request.

Install

npm install @kentico/gatsby-kontent-components gatsby-plugin-image

Also, add gatsby-plugin-image to plugins array in gatsby-config.js.

Typescript

Components exports their typescript definitions so that you know what data format you need to provide via props and what data format expect from function prop callback arguments.

Image element component

Images from Kontent can be displayed using the ImageElement component. This wraps the GatsbyImage component from gatsby-plugin-image, so ensure that you also install that plugin. This component will give the best experience for your users, as it includes responsive srcset, blur-up, lazy loading and many other performance optimizations. Automatic format optimization is always enabled. In many cases it can improve Lighthouse scores by 10-20 points.

The component takes all the GatsbyImage props, as well as the following properties. All are optional except image:

• image: the image object. This should include url, width and height.

• layout: see the gatsby-plugin-image docs

• width/height: see the gatsby-plugin-image docs

• aspectRatio: see the gatsby-plugin-image docs

• backgroundColor: displayed as a placeholder while the image loads

• options: ImageOptions: an object containing options passed to the Kontent Image Transformation API. Supported options: fit, quality, lossless.

  interface ImageOptions {
    fit?: 'crop' | 'clip' | 'scale';
    quality?: number;
    lossless?: boolean;
  }

Properties of the image object (e.g. width and height) are reflected in Kontent's image API query. Props of the ImageElement component (e.g. width and height) are reflected in the rendered DOM. If the optional props of ImageElement are omitted, the properties of the image object are applied.

You can find a showcase in the author.js on the development site.

import React from 'react';
import { ImageElement } from '@kentico/gatsby-kontent-components';
import { graphql } from 'gatsby';

export default Page = ({ data }) => {
  const avatar = data.author.elements.avatar_image.value[0];

  return (
    <ImageElement
      image={avatar}
      width={800}
      height={200}
      backgroundColor="#bbbbbb"
      alt={avatar.description}
    />
  );
};
export const query = graphql`
  {
    author: kontentItemAuthor {
      elements {
        avatar_image {
          value {
            url
            description
          }
        }
      }
    }
  }
`;

getGatsbyImageData

In case you need image data for GatsbyImage component, you can use an exported function getGatsbyImageData.

Showcase can be found in article.js in the development site.

  const imageData = getGatsbyImageData({
      image: avatar, 
      width: 800,
      height: 200,
      backgroundColor:"#bbbbbb"
  })

Rich text element component

Rich text elements from Kontent could be resolved to React components using "html-react-parser" as described in this article.

This package should make the usage easier. Basically by loading the rich text data and use these components to provide this data and resolution functions.

import {
  RichTextElement,
  ImageElement,
} from '@kentico/gatsby-kontent-components';

// ...

<RichTextElement
  value={richTextElement.value}
  images={richTextElement.images}
  links={richTextElement.links}
  linkedItems={richTextElement.modular_content}
  resolveImage={image => {
    return (
      <ImageElement
        image={image}
        alt={image.description ? image.description : image.name}
        width={200}
      />
    );
  }}
  resolveLink={(link, domNode) => {
    const parentItemType = contextData.type; // It is possible to use external data for resolution
    return (
      <Link to={`/${link.type}/partner/${parentItemType}/${link.url_slug}`}>
        {domNode.children[0].data}
      </Link>
    );
  }}
  resolveLinkedItem={(linkedItem, domNode) => {
    const isComponent = domNode.attribs['data-rel'] === 'component';
    const isLinkedItem = domNode.attribs['data-rel'] === 'link';
    return (
      <>
        {isComponent && <h1>Component</h1>}
        {isLinkedItem && <h1>Linked item</h1>}
        <pre>{JSON.stringify(linkedItem, undefined, 2)}</pre>
      </>
    );
  }}
  resolveDomNode={(domNode, domToReact) => {
    if (domNode.name === 'table') {
      // For options - check https://www.npmjs.com/package/html-react-parser#options
      return <div className="table-responsive">{domToReact([domNode])}</div>;
    }
  }}
/>;

Resolution scope

If you don't need to resolve anything, you could just provide value property.

Images

If you want to resolve images pass images and resolveImage properties.

• images have to contain at least image_id property
• resolveImage has one parameter image usually containing one record from images array
• when resolving images in Rich text element using Image element component, image object must follow data contract defined in Image element component section. Moreover, for correct resolution, the additional image_id identifier of the image is mandatory, as well.

Links to content items

If you want to resolve links to other content items pass links and resolveLink properties.

All other links (web URL, email, asset link) are not resolved. If you could use this functionality, please submit a feature request.

• links have to contain at least link_id property
• resolveLink has two parameter link basically containing one record from links array and domNode dome link element that could be used for i.e. getting the inner text of the current link domNode.children[0].data.

Content components and Linked content items

If you want to resolve images pass linkedItems and resolveLinkedItem properties.

• linkedItems have to contain at least system.codename property
• resolveLinkedItem has one parameter linkedItem basically containing one record from linkedItems array

Custom resolution for any other dom node

The general resolution method resolveDomNode is called for every DOM node, except for ones that are resolved specifically (described above). In the example above, all table elements will be wrapped with the div element. You could also return just a JSX if you want to replace the domNode completely.

If you want to resolve elements via resolveDomNode, you get the following parameters:

• domNode - DOM node from html-react-parser
• domToReact - method from html-react-parser to be able to extend the actual domNode as on the example