Add renderPlaceholder (#4190)

.changeset/few-planets-brush.md

@@ -0,0 +1,5 @@
+---
+'slate-react': patch
+---
+
+Added a `renderPlaceholder` prop to the `<Editable>` component for customizing how placeholders are rendered.

packages/slate-react/src/components/editable.tsx

@@ -34,9 +34,9 @@ import {
   getDefaultView,
   isDOMElement,
   isDOMNode,
-  DOMStaticRange,
   isPlainTextOnlyPaste,
 } from '../utils/dom'
+
 import {
   EDITOR_TO_ELEMENT,
   ELEMENT_TO_NODE,
@@ -98,6 +98,7 @@ export type EditableProps = {
   style?: React.CSSProperties
   renderElement?: (props: RenderElementProps) => JSX.Element
   renderLeaf?: (props: RenderLeafProps) => JSX.Element
+  renderPlaceholder?: (props: RenderPlaceholderProps) => JSX.Element
   as?: React.ElementType
 } & React.TextareaHTMLAttributes<HTMLDivElement>
 
@@ -114,6 +115,7 @@ export const Editable = (props: EditableProps) => {
     readOnly = false,
     renderElement,
     renderLeaf,
+    renderPlaceholder = props => <DefaultPlaceholder {...props} />,
     style = {},
     as: Component = 'div',
     ...attributes
@@ -225,6 +227,7 @@ export const Editable = (props: EditableProps) => {
         scrollMode: 'if-needed',
         boundary: el,
       })
+      // @ts-ignore
       delete leafEl.getBoundingClientRect
     } else {
       domSelection.removeAllRanges()
@@ -1046,6 +1049,7 @@ export const Editable = (props: EditableProps) => {
             decorations,
             node: editor,
             renderElement,
+            renderPlaceholder,
             renderLeaf,
             selection: editor.selection,
           })}
@@ -1055,6 +1059,29 @@ export const Editable = (props: EditableProps) => {
   )
 }
 
+/**
+ * The props that get passed to renderPlaceholder
+ */
+export type RenderPlaceholderProps = {
+  children: any
+  attributes: {
+    'data-slate-placeholder': boolean
+    dir?: 'rtl'
+    contentEditable: boolean
+    ref: React.RefObject<any>
+    style: React.CSSProperties
+  }
+}
+
+/**
+ * The default placeholder element
+ */
+
+export const DefaultPlaceholder = ({
+  attributes,
+  children,
+}: RenderPlaceholderProps) => <span {...attributes}>{children}</span>
+
 /**
  * A default memoized decorate function.
  */

packages/slate-react/src/components/element.tsx

@@ -15,7 +15,11 @@ import {
   KEY_TO_ELEMENT,
 } from '../utils/weak-maps'
 import { isDecoratorRangeListEqual } from '../utils/range-list'
-import { RenderElementProps, RenderLeafProps } from './editable'
+import {
+  RenderElementProps,
+  RenderLeafProps,
+  RenderPlaceholderProps,
+} from './editable'
 
 /**
  * Element.
@@ -25,13 +29,15 @@ const Element = (props: {
   decorations: Range[]
   element: SlateElement
   renderElement?: (props: RenderElementProps) => JSX.Element
+  renderPlaceholder: (props: RenderPlaceholderProps) => JSX.Element
   renderLeaf?: (props: RenderLeafProps) => JSX.Element
   selection: Range | null
 }) => {
   const {
     decorations,
     element,
     renderElement = (p: RenderElementProps) => <DefaultElement {...p} />,
+    renderPlaceholder,
     renderLeaf,
     selection,
   } = props
@@ -44,6 +50,7 @@ const Element = (props: {
     decorations,
     node: element,
     renderElement,
+    renderPlaceholder,
     renderLeaf,
     selection,
   })
@@ -98,7 +105,13 @@ const Element = (props: {
           position: 'absolute',
         }}
       >
-        <Text decorations={[]} isLast={false} parent={element} text={text} />
+        <Text
+          renderPlaceholder={renderPlaceholder}
+          decorations={[]}
+          isLast={false}
+          parent={element}
+          text={text}
+        />
       </Tag>
     )
 

packages/slate-react/src/components/leaf.tsx

@@ -2,7 +2,7 @@ import React, { useRef, useEffect } from 'react'
 import { Element, Text } from 'slate'
 import String from './string'
 import { PLACEHOLDER_SYMBOL } from '../utils/weak-maps'
-import { RenderLeafProps } from './editable'
+import { RenderLeafProps, RenderPlaceholderProps } from './editable'
 
 // auto-incrementing key for String component, force it refresh to
 // prevent inconsistent rendering by React with IME input
@@ -15,6 +15,7 @@ const Leaf = (props: {
   isLast: boolean
   leaf: Text
   parent: Element
+  renderPlaceholder: (props: RenderPlaceholderProps) => JSX.Element
   renderLeaf?: (props: RenderLeafProps) => JSX.Element
   text: Text
 }) => {
@@ -23,6 +24,7 @@ const Leaf = (props: {
     isLast,
     text,
     parent,
+    renderPlaceholder,
     renderLeaf = (props: RenderLeafProps) => <DefaultLeaf {...props} />,
   } = props
 
@@ -43,7 +45,7 @@ const Leaf = (props: {
     return () => {
       editorEl.style.minHeight = 'auto'
     }
-  }, [placeholderRef])
+  }, [placeholderRef, leaf])
 
   let children = (
     <String
@@ -56,27 +58,28 @@ const Leaf = (props: {
   )
 
   if (leaf[PLACEHOLDER_SYMBOL]) {
+    const placeholderProps: RenderPlaceholderProps = {
+      children: leaf.placeholder,
+      attributes: {
+        'data-slate-placeholder': true,
+        style: {
+          position: 'absolute',
+          pointerEvents: 'none',
+          width: '100%',
+          maxWidth: '100%',
+          display: 'block',
+          opacity: '0.333',
+          userSelect: 'none',
+          textDecoration: 'none',
+        },
+        contentEditable: false,
+        ref: placeholderRef,
+      },
+    }
+
     children = (
       <React.Fragment>
-        <span
-          ref={placeholderRef}
-          contentEditable={false}
-          style={{
-            pointerEvents: 'none',
-            display: 'inline-block',
-            width: '100%',
-            maxWidth: '100%',
-            whiteSpace: 'nowrap',
-            opacity: '0.333',
-            userSelect: 'none',
-            fontStyle: 'normal',
-            fontWeight: 'normal',
-            textDecoration: 'none',
-            position: 'absolute',
-          }}
-        >
-          {leaf.placeholder}
-        </span>
+        {renderPlaceholder(placeholderProps)}
         {children}
       </React.Fragment>
     )
@@ -99,6 +102,7 @@ const MemoizedLeaf = React.memo(Leaf, (prev, next) => {
     next.parent === prev.parent &&
     next.isLast === prev.isLast &&
     next.renderLeaf === prev.renderLeaf &&
+    next.renderPlaceholder === prev.renderPlaceholder &&
     next.text === prev.text &&
     next.leaf.text === prev.leaf.text &&
     Text.matches(next.leaf, prev.leaf) &&

packages/slate-react/src/components/text.tsx

@@ -3,7 +3,7 @@ import { Range, Element, Text as SlateText } from 'slate'
 
 import Leaf from './leaf'
 import { ReactEditor, useSlateStatic } from '..'
-import { RenderLeafProps } from './editable'
+import { RenderLeafProps, RenderPlaceholderProps } from './editable'
 import { useIsomorphicLayoutEffect } from '../hooks/use-isomorphic-layout-effect'
 import {
   KEY_TO_ELEMENT,
@@ -20,10 +20,18 @@ const Text = (props: {
   decorations: Range[]
   isLast: boolean
   parent: Element
+  renderPlaceholder: (props: RenderPlaceholderProps) => JSX.Element
   renderLeaf?: (props: RenderLeafProps) => JSX.Element
   text: SlateText
 }) => {
-  const { decorations, isLast, parent, renderLeaf, text } = props
+  const {
+    decorations,
+    isLast,
+    parent,
+    renderPlaceholder,
+    renderLeaf,
+    text,
+  } = props
   const editor = useSlateStatic()
   const ref = useRef<HTMLSpanElement>(null)
   const leaves = SlateText.decorations(text, decorations)
@@ -37,6 +45,7 @@ const Text = (props: {
       <Leaf
         isLast={isLast && i === leaves.length - 1}
         key={`${key.id}-${i}`}
+        renderPlaceholder={renderPlaceholder}
         leaf={leaf}
         text={text}
         parent={parent}

packages/slate-react/src/hooks/use-children.tsx

@@ -7,7 +7,11 @@ import { ReactEditor } from '..'
 import { useSlateStatic } from './use-slate-static'
 import { useDecorate } from './use-decorate'
 import { NODE_TO_INDEX, NODE_TO_PARENT } from '../utils/weak-maps'
-import { RenderElementProps, RenderLeafProps } from '../components/editable'
+import {
+  RenderElementProps,
+  RenderLeafProps,
+  RenderPlaceholderProps,
+} from '../components/editable'
 
 /**
  * Children.
@@ -17,10 +21,18 @@ const useChildren = (props: {
   decorations: Range[]
   node: Ancestor
   renderElement?: (props: RenderElementProps) => JSX.Element
+  renderPlaceholder: (props: RenderPlaceholderProps) => JSX.Element
   renderLeaf?: (props: RenderLeafProps) => JSX.Element
   selection: Range | null
 }) => {
-  const { decorations, node, renderElement, renderLeaf, selection } = props
+  const {
+    decorations,
+    node,
+    renderElement,
+    renderPlaceholder,
+    renderLeaf,
+    selection,
+  } = props
   const decorate = useDecorate()
   const editor = useSlateStatic()
   const path = ReactEditor.findPath(editor, node)
@@ -53,6 +65,7 @@ const useChildren = (props: {
           element={n}
           key={key.id}
           renderElement={renderElement}
+          renderPlaceholder={renderPlaceholder}
           renderLeaf={renderLeaf}
           selection={sel}
         />
@@ -64,6 +77,7 @@ const useChildren = (props: {
           key={key.id}
           isLast={isLeafBlock && i === node.children.length - 1}
           parent={node}
+          renderPlaceholder={renderPlaceholder}
           renderLeaf={renderLeaf}
           text={n}
         />

packages/slate-react/src/index.ts

@@ -3,6 +3,8 @@ export {
   RenderElementProps,
   RenderLeafProps,
   Editable,
+  RenderPlaceholderProps,
+  DefaultPlaceholder,
 } from './components/editable'
 export { DefaultElement } from './components/element'
 export { DefaultLeaf } from './components/leaf'

site/examples/custom-placeholder.tsx

@@ -0,0 +1,34 @@
+import React, { useState, useMemo } from 'react'
+import { createEditor, Descendant } from 'slate'
+import { Slate, Editable, withReact } from 'slate-react'
+import { withHistory } from 'slate-history'
+
+const PlainTextExample = () => {
+  const [value, setValue] = useState<Descendant[]>(initialValue)
+  const editor = useMemo(() => withHistory(withReact(createEditor())), [])
+  return (
+    <Slate editor={editor} value={value} onChange={value => setValue(value)}>
+      <Editable
+        placeholder="Type something"
+        renderPlaceholder={({ children, attributes }) => (
+          <div {...attributes}>
+            <p>{children}</p>
+            <pre>
+              Use the renderPlaceholder prop to customize rendering of the
+              placeholder
+            </pre>
+          </div>
+        )}
+      />
+    </Slate>
+  )
+}
+
+const initialValue: Descendant[] = [
+  {
+    type: 'paragraph',
+    children: [{ text: '' }],
+  },
+]
+
+export default PlainTextExample

site/pages/examples/[example].tsx

@@ -26,6 +26,7 @@ import SearchHighlighting from '../../examples/search-highlighting'
 import ShadowDOM from '../../examples/shadow-dom'
 import Tables from '../../examples/tables'
 import IFrames from '../../examples/iframe'
+import CustomPlaceholder from '../../examples/custom-placeholder'
 
 // node
 import { getAllExamples } from '../api'
@@ -50,6 +51,7 @@ const EXAMPLES = [
   ['Shadow DOM', ShadowDOM, 'shadow-dom'],
   ['Tables', Tables, 'tables'],
   ['Rendering in iframes', IFrames, 'iframe'],
+  ['Custom placeholder', CustomPlaceholder, 'custom-placeholder'],
 ]
 
 const Header = props => (