avoid setPrototypeOf

Author: kurkle

src/core/core.datasetController.js

@@ -149,20 +149,19 @@ function getFirstScaleId(chart, axis) {
 }
 
 function createDatasetContext(parent, index, dataset) {
-  return Object.setPrototypeOf(
+  return Object.assign(Object.create(parent),
     {
       active: false,
       dataset,
       datasetIndex: index,
       index,
       type: 'dataset'
-    },
-    parent
+    }
   );
 }
 
 function createDataContext(parent, index, point, raw, element) {
-  const context = {
+  return Object.assign(Object.create(parent), {
     active: false,
     dataIndex: index,
     parsed: point,
@@ -171,9 +170,7 @@ function createDataContext(parent, index, point, raw, element) {
     index,
     mode: 'default',
     type: 'data'
-  };
-  Object.setPrototypeOf(context, parent);
-  return context;
+  });
 }
 
 function clearStacks(meta, items) {

src/core/core.scale.js

@@ -282,27 +282,17 @@ function skip(ticks, newTicks, spacing, majorStart, majorEnd) {
 }
 
 function createScaleContext(parent, scale) {
-  return Object.create(parent, {
-    scale: {
-      value: scale
-    },
-    type: {
-      value: 'scale'
-    }
+  return Object.assign(Object.create(parent), {
+    scale,
+    type: 'scale'
   });
 }
 
 function createTickContext(parent, index, tick) {
-  return Object.create(parent, {
-    tick: {
-      value: tick
-    },
-    index: {
-      value: index
-    },
-    type: {
-      value: 'tick'
-    }
+  return Object.assign(Object.create(parent), {
+    tick,
+    index,
+    type: 'tick'
   });
 }