add placeholder extension

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

@@ -0,0 +1,54 @@
+<template>
+  <editor-content :editor="editor" />
+</template>
+
+<script>
+import { Editor, EditorContent } from '@tiptap/vue-2'
+import { defaultExtensions } from '@tiptap/starter-kit'
+import Placeholder from '@tiptap/extension-placeholder'
+
+export default {
+  components: {
+    EditorContent,
+  },
+
+  data() {
+    return {
+      editor: null,
+    }
+  },
+
+  mounted() {
+    this.editor = new Editor({
+      extensions: [
+        ...defaultExtensions(),
+        Placeholder,
+      ],
+    })
+  },
+
+  beforeDestroy() {
+    this.editor.destroy()
+  },
+}
+</script>
+
+<style lang="scss" scoped>
+::v-deep {
+  /* Basic editor styles */
+  .ProseMirror {
+    > * + * {
+      margin-top: 0.75em;
+    }
+  }
+
+  /* Placeholder */
+  .ProseMirror p.is-editor-empty:first-child::before {
+    content: attr(data-placeholder);
+    float: left;
+    color: #ced4da;
+    pointer-events: none;
+    height: 0;
+  }
+}
+</style>