feature: add generateJSON utility function to generate JSON from a HTML string

tests/cypress/integration/core/generateJSON.spec.ts

@@ -0,0 +1,29 @@
+/// <reference types="cypress" />
+
+import { generateJSON } from '@tiptap/core'
+import Document from '@tiptap/extension-document'
+import Paragraph from '@tiptap/extension-paragraph'
+import Text from '@tiptap/extension-text'
+
+describe('generateJSON', () => {
+  it('generate HTML from JSON without an editor instance', () => {
+    const html = '<p>Example Text</p>'
+
+    const json = generateJSON(html, [
+      Document,
+      Paragraph,
+      Text,
+    ])
+
+    expect(JSON.stringify(json)).to.eq(JSON.stringify({
+      type: 'doc',
+      content: [{
+        type: 'paragraph',
+        content: [{
+          type: 'text',
+          text: 'Example Text',
+        }],
+      }],
+    }))
+  })
+})