Element API

Element objects are a type of Node in a Slate document that contain other Element nodes or Text nodes.

interface Element {
  children: Node[]
}

• Behavior Types
  • Block vs. Inline
  • Void vs Not Void
    • Rendering Void Elements
• Static methods
  • Retrieval methods
  • Check methods

Element Behavior Types

Element nodes behave differently depending on the Slate editor's configuration. An element can be:

• "block" or "inline" as defined by editor.isInline
• either "void" or "not void" as defined by editor.isVoid

Block vs. Inline

A "block" element can only be siblings with other "block" elements. An "inline" node can be siblings with Text nodes or other "inline" elements.

Void vs Not Void

In a not "void" element, Slate handles the rendering of its children (e.g. in a paragraph where the Text and Inline children are rendered by Slate). In a "void" element, the children are rendered by the Element's render code.

Voids That Support Marks

Some void elements are effectively stand-ins for text, such as with the Mentions example, where the mention element renders the character's name. Users might want to format Void elements like this with bold, or set their font and size, so editor.markableVoid tells Slate whether or not to apply Marks to the text children of void elements.

Rendering Void Elements

Void Elements must

• always have one empty child text node (for selection)
• render using attributes and children (so, their outermost HTML element can't be an HTML void element)
• set contentEditable={false} (for Firefox)

Typical rendering code will resemble this thematic-break (horizontal rule) element:

return (
  <div {...attributes} contentEditable={false}>
    {children}
    <hr />
  </div>
)

For a "markable" void such as a mention element, marks on the empty child element can be used to determine how the void element is rendered (Slate Marks are applied only to Text leaves):

const Mention = ({ attributes, children, element }) => {
  const selected = useSelected()
  const focused = useFocused()
  const style: React.CSSProperties = {
    padding: '3px 3px 2px',
    margin: '0 1px',
    verticalAlign: 'baseline',
    display: 'inline-block',
    borderRadius: '4px',
    backgroundColor: '#eee',
    fontSize: '0.9em',
    boxShadow: selected && focused ? '0 0 0 2px #B4D5FF' : 'none',
  }
  // See if our empty text child has any styling marks applied and apply those
  if (element.children[0].bold) {
    style.fontWeight = 'bold'
  }
  if (element.children[0].italic) {
    style.fontStyle = 'italic'
  }
  return (
    <span
      {...attributes}
      contentEditable={false}
      data-cy={`mention-${element.character.replace(' ', '-')}`}
      style={style}
    >
      {children}@{element.character}
    </span>
  )
}

Static methods

Retrieval methods

Element.matches(element: Element, props: Partial<Element>) => boolean

Check if an element matches a set of props. Note: This checks custom properties, but it does not ensure that any children are equivalent.

Check methods

Element.isAncestor(value: any) => value is Ancestor

Check if a value implements the 'Ancestor' interface.

Element.isElement(value: any) => value is Element

Check if a value implements the Element interface.

Element.isElementList(value: any) => value is Element[]

Check if a value is an array of Element objects.

Element.isElementType<T Extends Element>(value: any, elementVal: string, ElementKey: string = 'type'): value is T

Check if a value implements the Element interface and has elementKey with selected value. Default it check to type key value