SlateJS: Adding Images and Links
Published: 2021-04-11 20:25:21

In the previous, we talked about setting up a simple SlateJS text editor. Now, we're going to add two new features to our text editor -- inserting an image and link.

# Toolbar

For us to start adding rich text functionality, we'll need to create a toolbar component.

```react
import { useSlateStatic } from 'slate-react';
...

const Toolbar = () => {
  const editor = useSlateStatic()

  const handleInsertImage = () => {
    const url = prompt("Enter an Image URL"); // For simplicity
    insertImage(editor, url); // will be implemented later
  };

  const handleInsertLink = () => {
    const url = prompt("Enter a URL"); // For simplicity
    insertLink(editor, url); // will be implemented later
  };

  return (
    <div className="toolbar">
      <button onClick={handleInsertImage}>Image</button>
      <button onClick={handleInsertLink}>Link</button>
    </div>
  )
}
```

Important things to note here are
- `useSlateStatic`: gives us an instance of our Editor which won't cause a re-render,
- `insertImage`: a helper function that will insert an image into our Editor
- `insertLink`: a helper function that will insert a link into our Editor

We can then use this component as a child of our `Slate` component. We do this so we can use `useSlateStatic`.

```react
const Editor = () => {
  ...
  return (
    <Slate ...>
      <Toolbar />
      ...
    </Slate>
  )
}
```

# `insertImage`

Our `insertImage` function will handle how we'll insert images into our Editor. We'll have to set some rules.

1. If the Editor isn't focused, we'll add the image at the end of the Editor.
2. If the Editor is focused on an empty Node or void Node (eg. image node), we'll replace the empty Node node with the image.
3. If the Editor is focused on a non-empty Node, we'll add the image after the Node.

```react
const insertImage(editor, url) => {
   if (!url) return;

  const { selection } = editor;
  const image = createImageNode("Image", url);

  ReactEditor.focus(editor);

  if (!!selection) {
    const [parentNode, parentPath] = Editor.parent(
      editor,
      selection.focus?.path
    );

    if (editor.isVoid(parentNode) || Node.string(parentNode).length) {
      // Insert the new image node after the void node or a node with content
      Transforms.insertNodes(editor, image, {
        at: Path.next(parentPath),
        select: true
      });
    } else {
      // If the node is empty, replace it instead
      Transforms.removeNodes(editor, { at: parentPath });
      Transforms.insertNodes(editor, image, { at: parentPath, select: true });
    }
  } else {
    // Insert the new image node at the bottom of the Editor when selection
    // is falsey
    Transforms.insertNodes(editor, image, { select: true });
  }
}
```

# `insertLink`

Now that we're able to insert images, let's add functionality to insert links. Similar to the images, we need to set rules.

1. If the Editor isn't focused, insert the new link inside of a paragraph at the end of the Editor.
2. If the Editor is focused on a void node (eg. image node), insert the new link inside of a paragraph below the void node.
3. If the Editor is focused inside of a Paragraph, insert the new link at the selected spot.
4. If a range of text is highlighted, convert the highlighted text into a link.
5. If the selected text consists of a link, remove the link and follow Rule #3 and #4.

```react
const createLinkNode = (href, text) => ({
  type: "link",
  href,
  children: [{ text }]
});

const removeLink = (editor, opts = {}) => {
  Transforms.unwrapNodes(editor, {
    ...opts,
    match: (n) =>
      !Editor.isEditor(n) && Element.isElement(n) && n.type === "link"
  });
};

const insertLink = (editor, url) => {
  if (!url) return;

  const { selection } = editor;
  const link = createLinkNode(url, "New Link");

  ReactEditor.focus(editor);

  if (!!selection) {
    const [parentNode, parentPath] = Editor.parent(
      editor,
      selection.focus?.path
    );

    // Remove the Link node if we're inserting a new link node inside of another
    // link.
    if (parentNode.type === "link") {
      removeLink(editor);
    }

    if (editor.isVoid(parentNode)) {
      // Insert the new link after the void node
      Transforms.insertNodes(editor, createParagraphNode([link]), {
        at: Path.next(parentPath),
        select: true
      });
    } else if (Range.isCollapsed(selection)) {
      // Insert the new link in our last known location
      Transforms.insertNodes(editor, link, { select: true });
    } else {
      // Wrap the currently selected range of text into a Link
      Transforms.wrapNodes(editor, link, { split: true });
      // Remove the highlight and move the cursor to the end of the highlight
      Transforms.collapse(editor, { edge: "end" });
    }
  } else {
    // Insert the new link node at the bottom of the Editor when selection
    // is falsey
    Transforms.insertNodes(editor, createParagraphNode([link]));
  }
};
```

# Custom Type `Link`

Now that we're able to insert links, let's make sure we're able to render a Link correctly.

```react
const Link = ({ attributes, element, children }) => (
  <a {...attributes} href={element.href}>
    {children}
  </a>
);
```

We can then update our `renderElement` function to include the new Link type.

```react
const renderElement = (props) => {
  switch (props.element.type) {
    case "image":
      return <Image {...props} />;
    case "link":
      return <Link {...props} />;
    default:
      return <Paragraph {...props} />;
  }
};
```

## Link Popup

Since we can't really tell what URL the link has, we can create a simple popup whenever we focus on a link. We can do that by updating our `Link` component.

```react
const Link = ({ attributes, element, children }) => {
  const editor = useSlateStatic();
  const selected = useSelected();
  const focused = useFocused();

  return (
    <div className="element-link">
      <a {...attributes} href={element.href}>
        {children}
      </a>
      {selected && focused && (
        <div className="popup" contentEditable={false}>
          <a href={element.href} rel="noreferrer" target="_blank">
            <FontAwesomeIcon icon={faExternalLinkAlt} />
            {element.href}
          </a>
          <button onClick={() => removeLink(editor)}>
            <FontAwesomeIcon icon={faUnlink} />
          </button>
        </div>
      )}
    </div>
  );
};
```

# Conclusion

With our rich text taking shape, we're starting to see the power of Slate and how you have the power to implement the way you want to.

# Demo

{% codesandbox 35inm %}