🐛 Run clipboard matchers against plain text pastes

This is a reimplementation of slab#3530

At the moment, if the clipboard pastes `text/plain` content and no
`text/html` content, the `Clipboard.convert()` function will completely
skip the matching logic.

This is surprising when registering text node clipboard matchers.

This change updates the `convert()` function to match the plain text
against the plain text matchers, just like we do with HTML.

Note that these matchers will run _before_ applying the formats for
["paste and match style"][1], so they won't match an element matchers
for the target formatting (which I think should be expected anyway).

[1]: slab#3927

packages/quill/src/modules/clipboard.ts

@@ -106,7 +106,8 @@ class Clipboard extends Module<ClipboardOptions> {
       });
     }
     if (!html) {
-      return new Delta().insert(text || '', formats);
+      const converted = this.convertText(text || '');
+      return converted.compose(new Delta().retain(converted.length(), formats));
     }
     const delta = this.convertHTML(html);
     // Remove trailing newline
@@ -123,8 +124,19 @@ class Clipboard extends Module<ClipboardOptions> {
     normalizeExternalHTML(doc);
   }
 
+  protected convertText(text: string) {
+    const doc = new DOMParser().parseFromString('', 'text/html');
+    const node = doc.createTextNode(text);
+    doc.body.appendChild(node);
+    return this.convertDoc(doc);
+  }
+
   protected convertHTML(html: string) {
     const doc = new DOMParser().parseFromString(html, 'text/html');
+    return this.convertDoc(doc);
+  }
+
+  private convertDoc(doc: Document) {
     this.normalizeHTML(doc);
     const container = doc.body;
     const nodeMatches = new WeakMap();

packages/quill/test/unit/modules/clipboard.spec.ts

@@ -522,6 +522,31 @@ describe('Clipboard', () => {
       expect(delta).toEqual(expected);
     });
 
+    test('runs a text node matcher on a plain text paste', function () {
+      const clipboard = createClipboard();
+      clipboard.addMatcher(Node.TEXT_NODE, (node, delta) => {
+        let index = 0;
+        const regex = /https?:\/\/[^\s]+/g;
+        let match = null;
+        const composer = new Delta();
+        // eslint-disable-next-line no-cond-assign
+        while ((match = regex.exec((node as Text).data))) {
+          composer.retain(match.index - index);
+          index = regex.lastIndex;
+          composer.retain(match[0].length, { link: match[0] });
+        }
+        return delta.compose(composer);
+      });
+      const delta = clipboard.convert({
+        text: 'http://github.com https://quilljs.com',
+      });
+      const expected = new Delta()
+        .insert('http://github.com', { link: 'http://github.com' })
+        .insert(' ')
+        .insert('https://quilljs.com', { link: 'https://quilljs.com' });
+      expect(delta).toEqual(expected);
+    });
+
     test('does not execute javascript', () => {
       // @ts-expect-error
       window.unsafeFunction = vitest.fn();