Add an argument to transformPasted indicating if paste is plain text

FEATURE: Pass an argument to `transformPasted` that tells the handler whether the paste is plain text.

Author: ocavue

src/clipboard.ts

@@ -44,7 +44,7 @@ export function parseFromClipboard(view: EditorView, text: string, html: string
   let inCode = $context.parent.type.spec.code
   let dom: HTMLElement | undefined, slice: Slice | undefined
   if (!html && !text) return null
-  let asText = text && (plainText || inCode || !html)
+  let asText: boolean = !!text && (plainText || inCode || !html)
   if (asText) {
     view.someProp("transformPastedText", f => { text = f(text, inCode || plainText, view) })
     if (inCode) return text ? new Slice(Fragment.from(view.state.schema.text(text.replace(/\r\n?/g, "\n"))), 0, 0) : Slice.empty
@@ -101,7 +101,7 @@ export function parseFromClipboard(view: EditorView, text: string, html: string
     }
   }
 
-  view.someProp("transformPasted", f => { slice = f(slice!, view) })
+  view.someProp("transformPasted", f => { slice = f(slice!, view, asText) })
   return slice
 }
 

src/index.ts

@@ -714,8 +714,9 @@ export interface EditorProps<P = any> {
   clipboardTextParser?: (this: P, text: string, $context: ResolvedPos, plain: boolean, view: EditorView) => Slice
 
   /// Can be used to transform pasted or dragged-and-dropped content
-  /// before it is applied to the document.
-  transformPasted?: (this: P, slice: Slice, view: EditorView) => Slice
+  /// before it is applied to the document. The `plain` flag will be
+  /// true when the text is pasted as plain text.
+  transformPasted?: (this: P, slice: Slice, view: EditorView, plain: boolean) => Slice
 
   /// Can be used to transform copied or cut content before it is
   /// serialized to the clipboard.

src/input.ts

@@ -718,7 +718,7 @@ editHandlers.drop = (view, _event) => {
   let $mouse = view.state.doc.resolve(eventPos.pos)
   let slice = dragging && dragging.slice
   if (slice) {
-    view.someProp("transformPasted", f => { slice = f(slice!, view) })
+    view.someProp("transformPasted", f => { slice = f(slice!, view, false) })
   } else {
     slice = parseFromClipboard(view, getText(event.dataTransfer),
                                brokenClipboardAPI ? null : event.dataTransfer.getData("text/html"), false, $mouse)