Apply suggestions from code review

Co-Authored-By: David I. Lehn <dil@lehn.org>
Co-Authored-By: Dave Longley <dlongley@digitalbazaar.com>

Author: 3 people

CHANGELOG.md

@@ -10,7 +10,6 @@
   defaults to `@id`.
 - Expanding/compacting type scoped contexts uses context before applying
   new versions to look for type scopes.
-- 
 
 ### Changed
 - Default processing mode changed to json-ld-1.1. Allows a 1.1 context to be

lib/compact.js

@@ -163,7 +163,7 @@ api.compact = async ({
     const inputCtx = activeCtx;
 
     // revert to previous context, if there is one,
-    // and element is  not a value object or a node reference
+    // and element is not a value object or a node reference
     if(!_isValue(element) && !_isSubjectReference(element)) {
       activeCtx = activeCtx.revertToPreviousContext();
     }

lib/context.js

@@ -66,7 +66,7 @@ api.process = async ({
   }
 
   // override propagate if localCtx has `@propagate`
-  if(_isObject(ctxs[0]) && '@propagate' in ctxs[0]) {
+  if(_isObject(ctxs[0]) && typeof ctxs[0]['@propagate'] === 'boolean') {
     // Retrieve early, error checking done later
     propagate = ctxs[0]['@propagate'];
   }
@@ -90,7 +90,7 @@ api.process = async ({
     // reset to initial context
     if(ctx === null) {
       // We can't nullify if there are protected terms and we're
-      // not processing a property term scoped context
+      // not allowing overrides (e.g. processing a property term scoped context)
       if(!overrideProtected &&
         Object.keys(activeCtx.protected).length !== 0) {
         const protectedMode = (options && options.protectedMode) || 'error';
@@ -259,7 +259,7 @@ api.process = async ({
       }
       if(typeof value !== 'boolean') {
         throw new JsonLdError(
-          'Invalid JSON-LD syntax; @propagate must be boolean valued',
+          'Invalid JSON-LD syntax; @propagate value must be a boolean.',
           'jsonld.SyntaxError',
           {code: 'invalid @propagate value', context: localCtx});
       }
@@ -279,7 +279,8 @@ api.process = async ({
         term: key,
         defined,
         options,
-        overrideProtected});
+        overrideProtected
+      });
     }
 
     // cache result