Expand values and subject references under typed scope.

Author: dlongley

lib/expand.js

@@ -152,7 +152,37 @@ api.expand = ({
 
   // recursively expand object:
 
-  if(!insideIndex) {
+  // First determine if any type-scoped context should be reverted; it should
+  // only be reverted when the following are all true:
+  // 1. `element` is not a value or subject reference
+  // 2. `insideIndex` is false
+  const typeScopedContext = activeCtx.previousContext ? activeCtx : null;
+  let keys = Object.keys(element).sort();
+  let mustRevert = !insideIndex;
+  if(mustRevert && typeScopedContext && keys[0] !== '@context') {
+    // check if element is a subject reference
+    if(keys.length === 1) {
+      const expandedProperty = _expandIri(
+        typeScopedContext, keys[0], {vocab: true}, options);
+      if(expandedProperty === '@id') {
+        // subject reference found, use type-scoped context to expand it
+        mustRevert = false;
+      }
+    } else if(keys.length <= 2) {
+      // check if element is a value
+      for(const key of keys) {
+        const expandedProperty = _expandIri(
+          typeScopedContext, key, {vocab: true}, options);
+        if(expandedProperty === '@value') {
+          // value found, use type-scoped context to expand it
+          mustRevert = false;
+          break;
+        }
+      }
+    }
+  }
+
+  if(mustRevert) {
     // revert type scoped context
     activeCtx = activeCtx.revertTypeScopedContext();
   }
@@ -163,8 +193,7 @@ api.expand = ({
       {activeCtx, localCtx: element['@context'], options});
   }
 
-  // look for scoped context on @type
-  let keys = Object.keys(element).sort();
+  // look for scoped contexts on `@type`
   for(const key of keys) {
     const expandedProperty = _expandIri(activeCtx, key, {vocab: true}, options);
     if(expandedProperty === '@type') {