fix to always default operation.data to an object

packages/slate/src/models/operation.js

@@ -126,6 +126,11 @@ class Operation extends Record(DEFAULTS) {
     for (const key of ATTRIBUTES) {
       let v = object[key]
 
+      // Default `data` to an empty object.
+      if (key === 'data' && v === undefined) {
+        v = {}
+      }
+
       if (v === undefined) {
         // Skip keys for objects that should not be serialized, and are only used
         // for providing the local-only invert behavior for the history stack.
@@ -134,9 +139,6 @@ class Operation extends Record(DEFAULTS) {
         if (key == 'value') continue
         if (key == 'node' && type != 'insert_node') continue
 
-        // Skip optional user defined data
-        if (key == 'data') continue
-
         throw new Error(
           `\`Operation.fromJSON\` was passed a "${type}" operation without the required "${key}" attribute.`
         )
@@ -311,7 +313,7 @@ class Operation extends Record(DEFAULTS) {
         value = v
       }
 
-      if (key === 'data' && value) {
+      if (key === 'data') {
         value = value.toJSON()
       }
 

packages/slate/test/models/operation/create/add-mark-without-data.js

@@ -23,5 +23,5 @@ export const output = {
     object: 'mark',
     type: 'b',
   },
-  data: undefined,
+  data: {},
 }