Use object rest spread.

Co-Authored-By: Dave Longley <dlongley@digitalbazaar.com>

Author: davidlehn

lib/frame.js

@@ -191,7 +191,7 @@ api.frame = (state, subjects, frame, parent, property = null) => {
         state.graphStack.push(state.graph);
         // recurse into graph
         api.frame(
-          Object.assign({}, state, {graph: id, embedded: false}),
+          {...state, graph: id, embedded: false},
           Object.keys(state.graphMap[id]).sort(), [subframe], output, '@graph');
         state.graphStack.pop;
       }
@@ -200,7 +200,7 @@ api.frame = (state, subjects, frame, parent, property = null) => {
     // if frame has @included, recurse over its sub-frame
     if('@included' in frame) {
       api.frame(
-        Object.assign({}, state, {embedded: false}),
+        {...state, embedded: false},
         subjects, frame['@included'], output, '@included');
     }
 
@@ -247,7 +247,7 @@ api.frame = (state, subjects, frame, parent, property = null) => {
             if(graphTypes.isSubjectReference(oo)) {
               // recurse into subject reference
               api.frame(
-                Object.assign({}, state, {embedded: true}),
+                {...state, embedded: true},
                 [oo['@id']], subframe, list, '@list');
             } else {
               // include other values automatically
@@ -257,7 +257,7 @@ api.frame = (state, subjects, frame, parent, property = null) => {
         } else if(graphTypes.isSubjectReference(o)) {
           // recurse into subject reference
           api.frame(
-            Object.assign({}, state, {embedded: true}),
+            {...state, embedded: true},
             [o['@id']], subframe, output, prop);
         } else if(_valueMatch(subframe[0], o)) {
           // include other values, if they match
@@ -308,7 +308,7 @@ api.frame = (state, subjects, frame, parent, property = null) => {
           util.addValue(
             output['@reverse'], reverseProp, [], {propertyIsArray: true});
           api.frame(
-            Object.assign({}, state, {embedded: true}),
+            {...state, embedded: true},
             [subject], subframe, output['@reverse'][reverseProp],
             property);
         }