fix core onBeforeInput logic to re-render only when necessary

lib/plugins/core.js

@@ -110,10 +110,9 @@ function Plugin(options = {}) {
     /**
      * The core `onBeforeInput` handler.
      *
-     * If the current selection is expanded, we have to re-render.
      *
-     * If the next state resolves a new list of decorations for any of its text
+     *
-     * nodes, we have to re-render.
+     *
      *
      * Otherwise, we can allow the default, native text insertion, avoiding a
      * re-render for improved performance.
@@ -128,17 +127,32 @@ function Plugin(options = {}) {
       const transform = state.transform().insertText(e.data)
       const synthetic = transform.apply()
       const resolved = editor.resolveState(synthetic)
+      let isNative = true
 
-      const isSynthenic = (
+      // If the current selection is expanded, we have to re-render.
-        state.isExpanded ||
+      if (state.isExpanded) {
-        !resolved.equals(synthetic)
+        isNative = false
-      )
+      }
 
-      if (isSynthenic) e.preventDefault()
+      // If the current node was empty, we have to re-render so that any empty
+      // placeholder logic will be updated.
+      if (state.startText.text == '') {
+        isNative = false
+      }
 
-      return isSynthenic
+      // If the next state resolves a new list of decorations for any of its
-        ? synthetic
+      // text nodes, we have to re-render.
-        : transform.apply({ isNative: true })
+      else if (!resolved.equals(synthetic)) {
+        isNative = false
+      }
+
+      // Update the state with the proper `isNative`.
+      state = isNative
+        ? transform.apply({ isNative })
+        : synthetic
+
+      if (!isNative) e.preventDefault()
+      return state
     },
 
     /**