add the character count extension

docs/src/demos/Extensions/CharacterCount/index.vue

@@ -0,0 +1,80 @@
+<template>
+  <div>
+    <editor-content :editor="editor" />
+
+    <div :class="{'character-limit': true, 'character-limit--warning': characters === limit}">
+      {{ characters }}/{{ limit }} characters
+    </div>
+  </div>
+</template>
+
+<script>
+import { Editor, EditorContent } from '@tiptap/vue-starter-kit'
+import Document from '@tiptap/extension-document'
+import Paragraph from '@tiptap/extension-paragraph'
+import Text from '@tiptap/extension-text'
+import CharacterCount from '@tiptap/extension-character-count'
+
+export default {
+  components: {
+    EditorContent,
+  },
+
+  data() {
+    return {
+      editor: null,
+      limit: 280,
+    }
+  },
+
+  mounted() {
+    this.editor = new Editor({
+      extensions: [
+        Document,
+        Paragraph,
+        Text,
+        CharacterCount.configure({
+          limit: this.limit,
+        }),
+      ],
+      content: `
+        <p>
+          Let‘s make sure people can’t write more than 280 characters. I bet you could build one of the biggest social networks on that idea.
+        </p>
+      `,
+    })
+  },
+
+  computed: {
+    characters() {
+      if (this.editor) {
+        return this.editor.state.doc.content.size - 2
+      }
+
+      return null
+    },
+  },
+
+  beforeDestroy() {
+    this.editor.destroy()
+  },
+}
+</script>
+
+<style lang="scss">
+/* Basic editor styles */
+.ProseMirror {
+  > * + * {
+    margin-top: 0.75em;
+  }
+}
+
+.character-limit {
+  margin-top: 1rem;
+  color: #868e96;
+
+  &--warning {
+    color: #f03e3e;
+  }
+}
+</style>