add the character count extension

packages/extension-character-count/src/character-count.ts

@@ -0,0 +1,41 @@
+import { Extension } from '@tiptap/core'
+import { Plugin, PluginKey } from 'prosemirror-state'
+
+export const pluginKey = new PluginKey('characterLimit')
+
+export interface CharacterCountOptions {
+  limit?: number,
+}
+
+export const CharacterCount = Extension.create({
+  name: 'characterCount',
+
+  defaultOptions: <CharacterCountOptions>{
+    limit: 0,
+  },
+
+  addProseMirrorPlugins() {
+    const { options } = this
+
+    return [
+      new Plugin({
+
+        key: pluginKey,
+
+        appendTransaction: (transactions, oldState, newState) => {
+          const length = newState.doc.content.size
+
+          if (options.limit && length > options.limit) {
+            return newState.tr.insertText('', options.limit + 1, length)
+          }
+        },
+      }),
+    ]
+  },
+})
+
+declare module '@tiptap/core' {
+  interface AllExtensions {
+    CharacterCount: typeof CharacterCount,
+  }
+}

packages/extension-character-count/src/index.ts

@@ -0,0 +1,5 @@
+import { CharacterCount } from './character-count'
+
+export * from './character-count'
+
+export default CharacterCount